What's the general etiquette on this these days? I'd never do it, unless I either had permission from the person who's number I'd given or I had good reason to believe the person in question would want the person looking for the number to have it.

But someone (a guy) asked me for a friend's (a girl said guy does not know by does fancy) phone number because he liked her. I didn't give it to him as I felt it wasn't the right thing to do.

But is this the correct, or at least accepted, action?