Where do you play? I play at Stars and have been 3-betting light, been 3-bet light by certain players, and I have even 4-bet light with success. I'm no maniac at this but if I have position and someone is raising a lot but not calling 3-bets I will do it more often. Esp. if they fold flop a lot, but you say they aren't. I do this often to blind stealers as well as it really narrows their calling range. I am no expert at this stuff so I may be off but it's worked for me lately. I will admit that the suckouts are really big down here and can cause some bad tiltage.