I think is one of those great big grey 'it depends' moments.
Among the Model Mayhem type crowd I've seen plenty of
models on the forums complaining about 'creepy' photographers who insist on getting a photo with them. Then again, I've seen a photographer with many images on his page with him and the
models, all fun poses where clearly both people are having a laugh and its part of a positive atmosphere.
At the professional level, there are guys like Terry Richardson who cop a lot of flak for the pervy way he gets in photos with
models and take shots that would be closer to porn that anything, right through to something like a recent blog post I saw from Chase Jarvis who, after shooting moby, jumped in the frame for a quick portrait with him.
This isn't a do or don't thing. It's about the way you go about doing it and the situation you are in at the time.