I have pretty strong feelings about this too. There are two main reasons for having the lite version: to allow you to test it running on your server, and to be able to get into the script a little bit if you aren't sure about purchasing it.

I can understand there are people that may not be able to afford the full version, or think the price is too much. But this doesn't mean that you should have the right to take the lite version and modify it to make it functionally equivilant to the full version. Just because it is possible, that doesn't mean you should or that it is right.
It's just like other trial software you download from the internet... you get 30 days, or some features are disabled.

There is alot of time and effort that is involved in creating a software package the size of vBulletin, and it just isn't fair not to pay for the right to use it.

-Chris