In theory there's no way you would be able to use the hacks without first having a license. However as vbulletin is freely available illegally, they try to restrict the amount of hacks getting out by making you register with your vbulletin license. However as a lot of the hacks get leaked illegally also.... The only thing a license really covers you for is "OFFICIAL" support for the board software and the hacks published.
In summary you need the license to download the hacks for the software which you should already have a license for.. If doing things by the book.
**EDIT Beaten**