YouTube & ©

So, a friend of mine wanted a brief tutorial on how to use Microsoft Movie Maker so he can compile/edit a home-video of a family holiday he has planned this summer. Anyway, because he had no footage to play with, I gave him a few pointers with the Windows-bundled software using some .AVI files I had to hand -- which just so happened to include recent episodes of 24, Caprica, Chuck and Heroes. We had some fun with the video, playing around with title screens, soundtracks, subtitles, audio clips, and whatnot. The result was a sort of cheapo, genre version of Harry Hill's TV Burp lasting nearly two-minutes, which I thought was amusing enough to post on YouTube.

Unfortunately, I was unaware that YT's copyright detection software is so good, and the video was immediately blocked from being uploaded. So, sorry, you won't be able to watch it. But one thing confuses me -- many of my "favourites" on YT are video mash-ups, or people re-editing trailers for comic effect, so how do these slip through the net? I mean, 90% of everything I look at on YT is copyrighted material, really! Music videos, film trailers, etc. Was I just unlucky to have my homemade video flagged, or are there ways and means to avoid YT's software spotting intellectual property? Any advice?

BTW, it's not that I'm particularly keen to "fight the system", because I understand the importance of copyright, but I was interested to know how so much of YT's content isn't getting blocked at the upload stage, whereas my humble effort was!