Replying to People trying to nab jackets and gear

So this weekend I was hiking some rails in the park and this dude came up and tried to steal my step brothers jacket(He hung it on this little plastic sign at the top of the park but we were right by it) we started yelling at him like what the fuck and then the asshole said this "I wouldn't have tried to steal it if I knew it was you guys right there" Well durr fucking urr. This made me very mad. Is anyone experiencing this shit more lately?