It truely is classless, but how long does your unconscious mind, controlled by base animal instinct, stare at them until your conscious mind says, "Stop, you are being a vulgar retch!" Then don't forget to add the time it takes for the two minds to debate the merits of continuing vs. turning away.
Even with the light speed synaptic respnse, this usually takes a good 5 seconds and by then the damage is donw. You look up in embarassment as the lady is glaring at you, knowing what you were thinking.
My thought is that it is the woman fault! If she had not worn that tight T-Shirt, I would not have been caught up it that primitive response. But then again, I have to thank her for the lack of foresight!