In the context of a debate, a hypothetical question is not a logical argument. That is, it does not have premises and a conclusion which follows from those premises. So if you want the question to carry logical validity, it must be embedded in a broader argument. For example, instead of asking "Does your proposed ethical framework allow [some action]?" we might use this argument:

1. Under your proposed ethical framework, [some action] must be either acceptable or unacceptable.
2. If it is acceptable, then your framework contradicts a widely held intuition.
3. If it is unacceptable, then that would seem to contradict what you have already told me about your ethical framework.
4. Therefore, I doubt that your ethical framework is correct.

The explicit form of this argument is important, because we can see the weakness of premises (2) and (3): Some people might reasonably disagree that the widely held intuition is correct, or we might have misunderstood the ethical framework in the first instance. Structuring the argument as a question masks these weaknesses and purports to shift the burden of proof onto our interlocutor, forcing them to explicitly rebut (2) or (3). This can be fair, for example if the ethical framework has been poorly explained and we want it clarified. But it is quite unreasonable to demand an account of every conceivable hypothetical once we're sure we understand their position. At that point, we should be shifting to the explicit mode of the argument, to make it clearer that we're no longer suggesting an incompleteness in our opponent's theory.

In the context of a debate, a hypothetical question is not a logical argument. That is, it does not have premises and a conclusion which follows from those premises. So if you want the question to carry logical validity, it must be embedded in a broader argument. For example, instead of asking "Does your proposed ethical framework allow [some action]?" we might use this argument:

1. Under your proposed ethical framework, [some action] must be either acceptable or unacceptable.
2. If it is acceptable, then your framework contradicts a widely held intuition.
3. If it is unacceptable, then that would seem to contradict what you have already told me about your ethical framework.
4. Therefore, I doubt that your ethical framework is correct.

The explicit form of this argument is important, because we can see the weakness of premises (2) and (3): Some people might reasonably disagree that the widely held intuition is correct, or we might have misunderstood the ethical framework in the first instance. Structuring the argument as a question masks these weaknesses and purports to shift the burden of proof onto our interlocutor, forcing them to explicitly rebut (2) or (3). This can be fair, for example if the ethical framework has been poorly explained and we want it clarified. But it is quite unreasonable to demand an account of every conceivable hypothetical once we're sure we understand their position. At that point, we should be shifting to the explicit mode of the argument, to make it clearer that we're no longer suggesting an incompleteness in our opponent's theory.

On the other hand, if your question is not intended as a logical argument at all, then of course your opponent may fairly refuse to answer. Your opponent might just as reasonably refuse to talk about the weather, to play Go Fish, or to do any number of other things which have nothing to do with the debate. The only exception is when you are specifically asking for clarification about your opponent's position, in which case a hypothetical may be a poor vehicle for your question. Hypotheticals sound like arguments, even when they are not intended that way.