The problem is that you can't easily verify whether someone is 12 or 14 with documentation so the checkbox is all they had. You can easily verify if someone is over 18 and there are systems in place to do so, which means it's highly likely if this takes place that ID is going to be required. (I mean I also just lied after COPPA, but I was pissed to lose so many accounts that I'd signed up for honestly in 95-99.)
Are the kids going to get around it? Yes. (And good, that's one way to develop a healthy skepticism as well as some systems thinking.) But it's going to be way harder and likely involve forging documents or impersonating particular adults. (I can see a reverse of a situation I had growing up where my parents used us as shields against piracy accusations: "Ooops, sorry, I'll talk to my kid. They're totally the one who downloaded this game." nudge nudge wink wink where children act through their parents - it's not like it's hard for a 15 year old to take their mom/dad's driver's license and use it). Those actions are more likely to be punished, whereas a simple lie is 'kids will be kids'.
Are the kids going to get around it? Yes. (And good, that's one way to develop a healthy skepticism as well as some systems thinking.) But it's going to be way harder and likely involve forging documents or impersonating particular adults. (I can see a reverse of a situation I had growing up where my parents used us as shields against piracy accusations: "Ooops, sorry, I'll talk to my kid. They're totally the one who downloaded this game." nudge nudge wink wink where children act through their parents - it's not like it's hard for a 15 year old to take their mom/dad's driver's license and use it). Those actions are more likely to be punished, whereas a simple lie is 'kids will be kids'.