A stack of pony pictures in a mailbox is hardly 4chanesque. 4chan hacks Facebook profiles and DDoSes IP addresses. This is nothing like that. It's not difficult to clean up/get rid of, it doesn't cause property damage, it doesn't do anything like that. If I
found a big stack of full-color pony pictures in my mailbox, I'd try to find the person who put them there and thank them, because they sure did spend a lot of ink on me.