A male friend of mine came over one afternoon so he could pose for photos for me. In one set, I put him in a Danish military issue gas mask, and attached a chain leash to a collar he brought over. Though he was also wearing boxer briefs, that was it. I posted a picture of him like this on all fours, staring perplexed at a bowl of water on the floor beneath him, and Facebook removed that and warned me that if I post something like it again, I could be indefinitely banned.
Facebook also banned a woman who had posted a photo of herself FULLY CLAD (in a PVC dress, with her knees together). And temporarily banned another male friend of mine who was fully clad in his photo, in which he had run up behind his fully clad girlfriend as she bent over to pick something up off the floor, and an opportunist snapped a photo that looked like dry-humping.
Facebook has a serious problem even understanding its own rules.