One way would be to ask for an update before we make a decision. By making an explicit statement that a decision will be taken in the future you're making it clear that this wasn't the decision.
Another would be to be explicit about asking for them to conduct an experiment or test, as those would unambiguously not be intended to be a final solution.
But you might then well find that the request to carry out an experiment to do X will sound equally nebulous. But at least it's clear you're not being told it's a decision to do X.
Practically change the scope of work to make an experiment to find which way is better. Though, come to think of it, then they’re likely to get mad at me for requesting extra work. Well, we just need to communicate more.
Extra politeness of mid-west sometimes before a hurdle in business process development, because it really slows down the brainstorming phase. And then companies end up with software that doesn’t serve their needs because someone didn’t feel like talking and we didn’t have the whole month to design a single screen.