The problem with stalking is unless they make it blatantly obvious in chat or message that they are following you around and what not to harass you, it's next to impossible to tell intent.

You get the stalker claiming they're doing the story or whatever and happened to be in the same area as their victim. That they were having fun with an emote and just happened to be around you at the time. And since chances are they'll get sent to different GM's or not connected to each other and therefore the stalker typically has to cross a line with the TOS in their stalking beyond that to get in trouble.