Most Helpful Girl
It really depends on the comment. A comment like "nice tits/ass" is unnecessary and something most women don't want to hear. I think a more formal and not as sexual compliment is almost always welcome, depending on the situation.
They go crazy in what sense? Do they get hyper from afar or do they actually walk up to him and make sleazy comments? If it's the former, then that's not really a double standard, and something I'd think is fine (considering guys stare a lot both close up and from afar, which basically is the same). But if it's the latter, yes, it's a double standard.