It's an agreement. We agree to abide by the TOS when we post. If there is a nudity flag rule, we, by posting, have agreed that we should use the nudity flag. True, sometimes people forget, and they should correct their mistake when it's pointed out to them. It's a commercial site that has rules, and we should follow them if we're going to use their service. Their site, their rules. Also, it's common courtesy to post a warning. Some people don't like nudity, and by not using the flag your inflicting your opinion on them. I feel sorry for people who have such problems with the human form, but I have no right to go out of my way to make them feel uncomfortable. Of course, parents. if your kid is looking over your shoulder and sees a naked body, it's partly your fault for taking the chance when the kid is around. Frankly, I'd be more concerned over exposing them to the violence in the galleries than the nudity. I'd rather have a kid used to the human body, and not think of it as something to be afraid of or ashamed of. I wouldn't want a kid to ever get used to violence, and accept that hurting someone or something else is at any time acceptable.