Poop in room

My son is an FDA at a boutique hotel in a large midwestern city. This weekend two separate rooms were left with poop in the bed and one also had poop on a towel. This happened once a couple months ago too. He said it appeared to be malicious, not just an unfortunate bathroom accident. Is this common?! I find it pretty unfathomable, so am very curious as to whether it happens at other places too.