[Bob T.]

UTG played like a fish. There is a 46% chance that he will either have an overpair, or a set on the flop. If he raises, and they all call, he is getting a lot better odds on the money that goes in than he needs to make this a posev play. If he raises and they all fold, he made 3/4 of a big bet on Jacks, and that is probably above average for him. If he raises, and he gets one caller, most likely, he has improved his eventual chance of winning by at least a third, this is one chance where you could protect a vulnerable hand preflop, by raising.

Its the same kind of scenario, when there is a raise in front of you, and you will be second into the pot with Js, Ts, or 9s, or AK, you don't know that your hand is best, but you can threebet, and you will very likely improve your chances of winning the pot.