to forum staff
 

this is in the license agreement:

vBulletin source code may be altered (at the owners risk), but the software (altered or otherwise) may not be distributed to entities beyond the license holder without the explicit written permission of Jelsoft Enterprises Limited.

I was wondering how do I know whether or not the hacks found here comply with this? How do I know if a hack doesn't? I'm a little confused, and I like to do things the legal way...

If it's posted here, odds are it's legal. Illegal activity is usually handled quickly by the staff.

Yep. And the hacks only give you instructions which file you need to edit and don't distribute modified files.

Yes we have a huge team of pirate-fighters-peace-keepers moderators who will usually catch anything bad before you even notice it. ;)
Basically, if someone posts a full file from vBulletin (be it original or modified), and didn't get our permission to do so, it's bad.