I can't say that they don't for sure, but if I was designing the videoID youtube uses for URLs, I'd put a check character in there. For the rare case where it m

I can't say that they don't for sure, but if I was designing the videoID youtube uses for URLs, I'd put a check character in there. For the rare case where it must be entered manually. Would be nice to know if you'd made a typo rather than just hitting a blank ID in the vast space of all possible video IDs.