This question came up during someone else's post and it never got properly settled.

Here's the hand:

Party Poker 2/4 Hold'em (9 handed) FTR converter on zerodivide.cx

Preflop: Hero is SB with T, T.
4 folds, MP3 raises, CO calls, 1 fold, Hero???

His only read on these two players were that they were "fishy." I frequently encounter situations like this with players that are tight. Against fishy players I would 3-bet since we can't limit their holdings, but what about against tight?

The hands that seem most likely for our tight opponents are overcards (perhaps an overpair). If we give them a total of 3 overcards (for the times MP3 or CO plays with AT, KT and other random hands), then they'll hit one their cards ~46 % of the time on the flop. Since we don't have position, it makes it more difficult for us to tell when they've hit and missed, or when they've got an overpair. Thus, against tight players, I would err against the 3-bet.

Is this thinking right? Am I too passive?

And, if you wouldn't three-bet, what would you do? Call, and scope the scene on the turn? Fold, god forbid?