Would you get in trouble for lying about your age on something?

[Jacob__mybb_import1]

If a website requires you to be 13, it's because of the COPPA (Children's Online Privacy Protection Act). It governs popular websites that collect personal information from children (defined as everyone under 13 in the law.) Since complying with the law can be difficult (you have to get the kid's parent's permission for them to use the site, and you have to prove that it really is the parent) a lot of sites just choose to ban everyone under 13.

These websites probably don't stalk everyone online to find out how old they are, but if they find out you're not old enough they will usually ban you. I know it's happened to a few underage YouTube users that had their videos get extremely popular.