the point is that it's a bug that a simple copy/paste of the address will end up double posting the video for many people......it's happened enough to warrant an "explaination on how to post youtube videos", which is how people already do it to begin with, but because of the bug it fails regardless.
in every other forum i've used that's using later versions of vbulletin, all i have to do is copy the url in the address bar from the video, paste it into the message, and presto......one video. no edits, no deletes, no removing hyperlinks, just copy/paste and BAM. should always be that easy. apparently it is for some users and not for others.