That's too narrow a question. The actual question you want to ask them is what their plans are for the domain. Whether they'd sell it to someone who will offer forwarding service is a sub-question - it's one possible plan for the domain, but you don't want to come up with every possible plan and ask them one by one, "do you plan to do this?". See if they'll tell you what they do plan to do, not just yes or no on whether they plan to do one specific thing.