For a while I've known that "sugar daddies", i.e. wealthy older men are stalking young women on Instagram and offering money in exchange for sex, nude photos, etc. My wife, who looks like she's 21-23 complains about getting these messages all the time and shows them to me. It's gross, but talking with some friends who have teenage daughters last night, I discovered it's a lot more sinister.Some of these men are propositioning underage teens (14, 15 years old). They offer, e.g. $700/week for just conversation in the beginning, and then that escalates to asking for nude photos and who knows what else.Some friends of the girls, just 14 and 15 years old, are actually involved in this, and have shared screenshots of the bank deposits to prove it's real. This is in Vancouver, Canada, but I assume it's happening elsewhere too.It makes me really mad. Why are adult men with no contacts in common allowed to send messages to underage girls? Facebook knows your age and gender and contacts. Even if you have a public profile, this just shouldn't be permitted. That seems like the most simple and basic of protections and it hasn't been done.How are these predators so brazen as to proposition children on Instagram without consequences? Are Instagram messages end-to-end encrypted? I'm a big fan of end-to-end encryption, but now I'm seeing some flaws with the idea.If you have children, talk with them to make sure their Instagram account privacy settings are activated. I don't think it's a good idea for children to have a public account.