If a person claims to know anything could it be disproven by saying 'prove that we are not in a simulation'?
Yes, and this his is a very simple logical point.
"I know that p" implies "p is true". This is fundamental to the concept of knowledge.
And if p is true, then there is no possibility that p is false. Thus, if I know that p, then there is no possibility that p be false. However, if you don't know that there is no possibility that p be false, then you cannot exclude that p is false, and therefore it is possible, for all you know, that p be false, which falsifies your claim that you know that p is true (see note on possibility).
Please note the distinction between not knowing that there is no possibility that p is false, and p actually being false, just as there is a distinction between ignoring that p is false, and p actually being false.
Thus, an argument from ignorance can only at best falsify a claim to knowledge, not whether what is claimed to be true is in fact false.
Another crucial point is the question of what it is we are talking about when we claim to know that p is true.
The claims we make need to be interpreted in context. It may be true that I know that John Fitzgerald Kennedy is dead, but it wasn't true in 1962. That is, in 1962, the same claim would have been false, presumably.
That being said, there is one context that doesn't suffer interpretation: reality. While there are different times, different places, even possibly different John Fitzgerald Kennedy, there is one reality and there only one reality.
We can argue for example that even if we live in a simulation, it is possible to know that the sky is blue since we would in effect be talking of the simulated sky being blue, which may indeed be simulated as blue.
The same goes for, say, Quantum Physics and love. We are making claims about things as we think of them. Thus, my simulated mind may well represent correctly the simulated universe as obeying the laws of Quantum Physics as I think of them, provided the simulation is such that the simulated universe does obey QM laws as my simulated mind would think of them.
However, it may also be that although Alice sees the simulated sky as blue, the simulated sky is in fact simulated as not blue at all. Maybe, in our simulated universe, blue is only in Alice's simulated mind. In which case, she doesn't know that the simulated sky is blue since it is indeed not blue at all.
In other word, a simulation would void the notion that we could possibly know anything.
The fundamental reason is this: reality.
As we think of it, there is just one reality. A simulated reality isn't reality. To know that p is to know that p is true in reality. Claims to knowledge are thought of as true of reality, never of some simulated reality. This is the context of our interpretation of any claim to knowledge. And in a simulation, all we could possibly know would be the simulated reality, not reality.
And this would in effect void our notion of knowledge.
We all claim to know things all the time and very often when we don't in fact know what we are talking about. For example, some Joe may claim to know that monkeys don't fly. Suppose now that the next day a new species of monkeys is discovered and that these monkeys do fly! This would falsify the claim that monkeys don't fly and therefore Joe's claim that he knew that monkeys don't fly.
However, the most important point is that although Joe's claim is falsified only the next day, his claim was in fact already false the moment he made it. Thus, Joe didn't know, and never knew, what he had claimed to know that monkey didn't fly.
Usually, we genuinely believe we know what we claim to know. Yet, experience shows again and again that we can be wrong, and it is the simple possibility of being wrong, even if it is that we might be wrong, which falsifies our claims to knowledge.
I know that p implies that p is true. If I know p, then p is true. And if p is true, then there is no possibility that p is false. But if I don't know that there is no possibility that p is false, I don't know that p is true, which falsifies my claim to knowledge.
That in itself won't stop people claiming they know. This is entirely a practical matter.
In effect, whatever we believe we know to be true may in fact be false and there isn't much we can do about that. Most of the time, however, if you are somewhat conservative and prudent and reasonable in whatever claims you make, you won't be contradicted by the facts of the matter.
It is a fact of life that we will claim that p whenever we happen to believe with a high enough degree of confidence that p is true.
Thus, even though most of the time we don't know that p, we will nonetheless claim that p just because we believe that p, and because from experience we believe that most of the time, we won't be contradicted by the facts of the matter.
In practice, it is worth claiming you know all sorts of things again and again, even if it is not true that you know them, because if you are reasonable in your claims, experience shows that you won't be contradicted so often as to damage your standing in society. In other words, we don't feel like we need to fuss too much about our claims to knowledge.
This only apply to everyday life but it is everyday life that drives the way we use basic words like "know" and "believe". Hence, we will use the word "know" even when in fact we only believe, and this merely because we also believe we will get away with it, at least most of the time.
There is another aspect to the question, though, somewhat more subtle, but your question is right on spot.
An argument from ignorance should identify a possibility and not everything will do in that respect. For example, if you say, well, you don't know that p because you don't know that it is not possible that q and not q. This wouldn't work because in fact we do know that it is not possible that q and not q.
There is another case of ineffective argument from ignorance and this is when the situation that you are supposed to ignore whether it is possible or not just doesn't make sense. It is my opinion that the notion that we are in a simulation is nonsensical.
However, irrespective of whether my opinion on this is correct or not, the fact remains that nonsensical situations are ineffective for an argument from ignorance. We need to understand what it is we are supposed to not know that this isn't the case. The reason for that is simple. If we don't understand what is the situation involved in the argument, then we won't be able to decide whether we actually don't know that it is not the case.
Note on possibility
The notion of possibility I am referring to here is epistemic possibility: p is possible from your point of view whenever you don't know that p is false.
For details, see https://en.wikipedia.org/wiki/Epistemic_possibility.
Any notion of probability is entirely irrelevant to epistemic possibility. Epistemic possibility is a direct consequence of our notion of knowledge. If you don't know that something is false, then, for all you know, it may be true, i.e. it is possible.