This is wonderful. I'm off to limit my visits to daily, or maybe twice-daily if I login once in the morning and once at night. Will this kick you off in the middle of writing a comment? That's my one qualm about it - that I'll start writing a response and then won't be able to submit it because maxvisit has timed out. Maybe exempt the comment-posting URL (it should block you from further reloads afterwards, though)?
No, it doesn't apply till the server tries to generate the page following the submission. If you want to know what it's like, just set maxvisit to 1 and try it.