[wyrd]

Limping UTG has to do with pot odds preflop. With small pairs you want a lot of people in the pot to get good odds on the set, because small pairs have little hope of winning unless they flop a set. There's just no point in getting involved in a small pot with little to no chance of winning. So when you limp UTG, you have no way of knowing how many limpers you'll get with you. But in late position, you know how many people are already in the pot, so you can better judge if that 22 is worth playing or not. Also, in late position, you can possibly steal the pot if you miss your set and no one has shown any aggression on a ragged board.