This was new to me, I tried to get the direct link to clip on Youtube, but found out you must sign in because of the content. Then you embed it on ESR no problem!
I don't understand, or you missed the point. I did remove the embedding part from the url and got a normal looking youtube link. I meant to send the link but tested if it works, turned out it requires login to verify your age. Plus the direct embedded link doesn't work either without signing in. My wild guess is that it has to do with person (tourist :)) claiming to be over 18 so he can access the material, and YT codes/decodes the URL then differently. Just a hunch ofcourse, maybe someone can explain.
your method was putting it in the embed tag (?):
[ youtube=http://www.youtube.com/v/MSc0agGNJkw]
now that wors fine, but you can also just take http://www.youtube.com/v/MSc0agGNJkw and watch it, even if its flagged. that worked for me a few times, maybe they fixed it though