I definitely agree with not letting people post copyrighted videos, just about every other forum I know of doesn't allow it either. It's called CYA (cover your ass), people.
That said, I have downloaded copyrighted stuff before, but in the case of bike videos I usually either stop watching halfway through, or watch it a couple times and then buy the video if I liked it. I still need to buy Can I Eat, and I'll buy the Fit video when it's out (no, I'm not going to upload it)