They are intentionally planting a false seed when they really intend to go in another direction. It reminds me of Agamemnon in book 2 of the Illiad: https://www.sparknotes.com/lit/iliad/section2/.
What I find insidious about this kind of behavior is that although they claim that it is to encourage the team to not be shy speculating on new ideas, it seems as though the true purpose is to make the team lead appear smarter that the other team members. It's a kind of reverse psychology. If everyone is throwing out spontaneous ideas, some (probably most) will be bad. Some ideas are very dumb and are easily dismissed. Sometimes however it takes time to work through the subtleties and see the problems. If the leader deliberately seeds a bad idea and then is able to quickly point out some very subtle problem, it makes them look like a genius relative to others who would need more time to see that issue. That is why it seems manipulative to some of us.
