Calling someone a "Stalker" whether as a joke or not could be taken the wrong way. As police could get involved if someone is referred to as a stalker, and there could even be a case on harassment or stalking if it is in fact taken. But even saying 'bomb' in an airport either as a joke or not could lead to some serious problems. It would be the same as saying 'stalker' as someone could get seriously scared or rumors could appear. It would be much better not to.
But some people KNOW that it is a joke. I know that because me and my friends call each other stalkers all the time, and we KNOW that it's a joke. If we call our friends idiots, stupid, dumb, and sometimes morons or losers, isn't stalkers at least the least bit less offensive? I mean, if your friend came up to you like, "HI IDIOT!" , would you mind? I mean, they're your friend. Even if it was a stranger, you most likely know that they're not really serious. So, if your friend was like, "HI STALKER!" that would be about the same as, "HI IDIOT!" You'd probably just call back a name.
Calling names seems pretty normal to me, at least...
Come on, admit it, we've all called our friends names. Calling someone a stalker is nothing compared to what other things we call our friends... Typical conversation with you friends be like,
"Hey, you went to Walmart yesterday..."
"How do you know?... STALKER!"
Very typical, just a joke, you're not gonna go into jail for that. I do think that calling someone a stalker as a joke is normal and happens often between friends.