I'm a huge fan of men NOT looking at my cleavage. It's not flattering, it's insulting. Flattering is a nice compliment, or a nice smile, insulting is staring at my private parts.
If the OP looks, and doesn't get bad reactions that's fine; but don't start assuming what you're doing will fly with all girls.
I've had a case of this... he stared and stared and stared until I said "hey sir, mind looking elsewhere?" He did for a move or 2 then back to my boobs... I left him in the middle of the dancefloor. Mean? Maybe. Did I feel violated? Yeah pretty much.