When you want to buy alcohol, you show a cashier your ID, you pay and you leave. There is not a digital record of your ID being used to purchase alcohol at that exact location at that exact time.

The problem isn't with the idea of keeping kids off social media, it's with the infringement of privacy that necessarily comes with one of the only ways society has figured out to effectively enforce that policy.

"We shouldn't prevent children from working in factories because that might be a privacy violation!" is an emotionally-charged straw-man of my argument. Please calm down and argue against the argument I'm actually making, not the much weaker argument that you wish I was making.