You are right, I didn't think that far. My main point, though, was that IMHO shipping GPL software in violation to the licence doesn't free you from the GPL's obligations, since that doesn't terminate the agreement.
As to the discussion below whether you have to explicitly agree to a contract, at least in Swiss law (which is the only one I have the faintest knowledge about) there are three ways to enter a contract:
- written, by signature
- by taking an action that implies your intention to enter the contract (this is called "stillschweigend", which literally means tacitly, in German)