Most people who've been juggling for awhile don't need too much additional practice to be able to do at least a few blindfolded catches just because of how consistent your throws get after awhile.

The other thing that's interesting is how pattern recognition in flying things people aren't generally used to seeing develops. I used to play ultimate, and when people start learning how a frisbee flies they might be susceptible to chasing it down by following along the path of the disc rather than moving directly to where it's going to end up. This is sometimes called dogging the disc because (many) dogs do the same thing. But then you learn to "read" the disc and you can tell by the flight path and angle of the disc where it's going to land.