If people walk in to Best Buy today...and are able to buy the Galaxy Nexus, activate it, and leave....then this will officially have been one of the worst phone launches in history.
To allow a phone to sell (accidentally even), that has yet to be officially launched, and before Verizon even begins to sell it, will only show that Verizon has lost control of this product. They'll have only themselves to blame. Unfortunately for Best Buy, they will most likely be hit with some heavy fines. It has happened before, I use to work for Best Buy, some six years there, and releasing product before official word will usually result in a costly fine.
Today will be interesting nonetheless, and I have no doubt some people will in face score a Galaxy Nexus from BBY. This will be quite embarrassing for Verizon.