[cougar62]

It's not even a matter of whether it's unethical or "not nice", you're putting yourself in a very -EV situation by folding to let the disconnected player "stay afloat". If it's multiway, is everyone at the table going to agree to let everyone keep their blinds, to keep things equal, until if and when the disconnected player gets back? Because if not you'll be giving up your chances to steal and others will still be playing normally (and probably exploiting the situation). And, if by some chance you did end up at a table full of nice and honorable souls, and everyone just folded around for a while, soon the blinds would reach a point where it's a crapshoot, and any skill edge you might have on the field is shot.

Really the fairest, smartest, and most +EV thing to do is for everyone to continue to play at their best, exploiting the situation as they can. I hate when the person to my left disconnects, because then I'm faced with tougher defending decisions out of the SB, knowing others have (probably) widened their ranges. Yet another reason not to give them a break.

If it's heads up, then I guess it's a judgement call. You can speed call as fast as you can to wear him down or stall a little to see if he comes back.