There's some very obvious ways to prevent that. One way is "here's a list of ten candidate features we might prototype this week/month/quarter/release, but you

There's some very obvious ways to prevent that. One way is "here's a list of ten candidate features we might prototype this week/month/quarter/release, but you can only pick one". Or ask users to rank them, and only pick the consensus #1-ranked. The ensuing dialog can be informative.