YouTube aren't likely to have dangerous files on their servers though.
They may do, I don't know, but I'd say they're pretty secure.
FLV, SWF or any HTML - it's a bad idea to allow.
No, no option in VB but you can try this.
https://vborg.vbsupport.ru/showthread.php?p=1555453
Not currently working for me (3.7.1) so I don't have this hack installed right now until someone can help.