While I can appreciate your stance, I am not sure that's the best way to handle it. If what they were doing bothered me that much I'd just decline the offer and be done with it.

Running off at the mouth like that and indeed acting on it by turning them in is a good way to cause a lot of problems for yourself.............especially if it's a "friend". Telling them your stancein one thing..............threatening them is anotherimo.