And that isn't even what I'm talking about.
But it is what I'm talking about. I'm saying there are be circumstances under which "asking someone out" actually is harassment (morally, not legally), and why "there should not normally be a problem" is a reasonable answer from a lawyer: because actions never exist in a vacuum. Most of the time guys only ask a girl out if they've been given social cues to indicate that the answer may be "yes"; some of the time guys are a bit clueless and ask even though they've not been given any cues, or if they've been given "no" cues; but there are circumstances in which a guy asking is just one instance of a pattern of obnoxious behavior.
Another example, same person, was there was a fellow who brought work in some times, and managed to "accidentally" touch her butt a number of times.
I can understand why your coworker didn't want to report it to HR. But seriously, that guy was in the wrong. Your coworker managed to deal with the situation (by calling in another guy to help), but she shouldn't have had to deal with it at all. Don't you agree?