In terms of legal risk, this move almost makes me think that Palm is trying to provoke Apple into filing a lawsuit. The danger for Palm in such a suit is with all of the former Apple engineers now working for Palm. (There are many.) Did they use inside knowledge of the iPod/iTunes USB interface to implement the WebOS “media sync” feature? Palm’s not stupid — or at least Jon Rubinstein is not — so I would wager that Palm was careful to “clean-room” reverse-engineer the protocol. But if Apple sues, Palm would be forced to prove this in court, and in the meantime, they could be faced with the public perception that they’ve stolen Apple’s IP.
It’s one thing for Apple not to facilitate syncing with 3rd-party (non-Apple) players, but another altogether to actively go out of their way to stop it happening. Can you imagine the fallout if Microsoft were to add code into the SMB protocol that blocked access to non-Microsoft systems?
Apple effectively monopolises the portable media player market, and if they resort to Microsoft-in-the-90s style tactics to hold on to that monopoly, they could find themselves on the wrong side of the US Department of Justice.
I suspect Apple won’t take any “official” action to prevent Palm’s reverse-engineered syncing, since that would be anti-competitive. What they might do is release an iTunes software update that “accidentally” breaks the Palm syncing engine. If this were to happen, it would be extremely difficult for Palm to prove, in a legal sense, that Apple had deliberately broken compatibility. From an ethical point of view however, there would be no ambiguity.