[Potassium]

If you have to question whether what you're doing is legal or not, then you probably shouldn't be doing it. If that isn't the reason that you're asking then you don't really need to know the answer.

As far as I'm aware, SA-MP wouldn't get shut down because of the actions of one server, it'd be the server owner (and/or other people involved) that get(s) penalised. It wouldn't affect SA-MP unless lots and lots of server owners were using SA-MP to commit illegal activities.