I've watched multiple friends get stalked. Sometimes for nearly an hour (with the person following them from zone to zone and spamming). In one situation when the person being stalked didn't respond, the stalker just spammed all their friends (including me). To my knowledge nothing was ever done regardless of reports from multiple people. I understand it's likely difficult for a GM to follow a player around and observe inappropriate behaviour, but at the same time, allowing people to just free-reign harass someone seems problematic.

It would be nice if GMs could come up with a system to deal with this type of behaviour. Everyone should be able to enjoy the game without facing regular harassment.