I think our general standard is pretty close to what twickster expressed above.
In GQ, I may close a thread at the request of the OP if it’s a simple question that has been completely answered. However, if I think there is a potential for more information to be added or further discussion I may leave a thread open even if the OP is satisfied and requests closure.
I will generally NOT close a thread just because the OP doesn’t like or disagrees with the information being provided.
The most frequent cause of thread closure in GQ is if a fight has broken out or a hijack is taking place, and it has become too much of a mess to move to GD or another forum. In this case I’ll close it with a suggestion to open a new thread in an appropriate forum.