I gotta agree with Ron on this one. The MP guys is not really my concern here, especially since you have a read on what he is willing to do. If you have an UTG player with TAG stats over a decent number of hands I would be highly confident that his open indicated he woke up with something pretty substantial to start and with well over 100BB’s I can’t see jamming with the 88 (screams to me: “Call, I have a hand I don’t want to fold but it isn’t big enough for me to want to really play”). Given your position some small percentage of the time I am willing to flat an preflop raiser out of the SB from a tight player with a decent starting hand (77+, AJs+, something like that), and a reasonable read on what he could be holding, see what the flop brings (either I connect or it is something that hugely misses his range) and evaluate whether or not I have an opportunity to make a play. There are a lot more options at that point (you hit your hand, scare cards come down, etc) that can give you unearned credibility with your bets given that you were willing to play the hand out of the SB, but this is a fairly rare condition for me and I usually try to avoid pulling the stunt.