Does Google Reset Links To Zero?

At Domain Round Table 2008, Matt Cutts mentioned that Google sets the links to zero or near zero on domains that change hands. Aaron Wall gave a good reason as to why they want to do this. Google doesn't want to set up big arbitrage opportunities for smart SEOs who know the real value of old domains.

I recently tested this and moved a site to a new registrar and new IP address and nothing happened. In fact, the site gained several spots for its main keyword. Previously the site was sitting on the same IP with three other sites that were fairly similar. This was the reason for the move in the first place.

This doesn't mean that Google is lying, but it does mean that it's not a black and white issue. I think links are reset only under certain circumstances.