Pretty sure the size was 64. And my favorite trivia about tribes was that skiing was entirely unintended by the devs; it's made possible by a bug in the physics engine. But people had so much fun with it, and it became such a core part of gameplay, that when the (disastrous) sequels were written (Tribes 2 and Tribes: Vengeance) it was preserved intentionally.
Don't have mod points atm, or I'd do it myself, but mod parent up for interesting. I like the idea; I wish there were any way it would ever happen, but (whether you're joking or not) it's a cool thing to think.
It's ContentID. They do have humans who go through and review (they absolutely refuse to say how many), but ContentID does 90% of it these days. I spoke with one of the developers working on the system last fall, and they essentially consider it to be the Holy Grail of not having to waste time on DMCA notices. What's most likely is that in your case, the owner of the content hasn't asked YouTube to do anything about it, so they're merely flagging it, informing you, and not taking anything down. Compare to the big labels, which have YouTube take down flagged videos or, in some cases, give the labels a cut of the advertising revenue alongside them.
"A complex system that works is invariably found to have evolved from a simple system that worked." -- John Gall, _Systemantics_