Actually, I doubt that correct spelling and punctuation is much of an indicator in the algorithm. Adults posing as children will try to talk like children, so they'll be dumbing down their conversation too. In fact, I suspect they may overcompensate.

I imagine it's looking more for incorrect usage of slang, usage of slang that's no longer current, et cetera.

Agreed. Now the kids who happen to spell correctly, use larger words and proper punctuation will be further isolated from everyone else. Hooray for reinforcing the status quo!

Indeed, because it's pattern based - it does not automatically assume that the adult is "smarter", but that any person whose communications are too far off the normal curve will, presumably, get flagged. Kids, be like everyone else, or we'll send the SWAT after you! (j/k - I do think this is a good thing)

My thoughts entirely. If this was ever used in practice it would need substantial improvement; it could create awkward problems for the fathers of well spoken children.