Apple and law enforcement are completely in the wrong for their actions against Gizmodo in this case IMO.
a. Gizmodo tried to have Apple confirm that it was indeed one of their products he had in his possession as soon as he acquired it, and Apple vehemently denied it. That means Gizmodo was in the clear to do whatever he wanted with it. So he popped it open and wrote a review about it. Only after the review came out did Apple acknowledge that indeed it was their prototype.
b. As soon as Apple confirmed in writing that it was their prototype, Gizmodo promptly returned the item to Apple.
c. AFTER Apple received their lost prototype they filed a criminal complaint for the item they already had in their possession as stolen by Gizmodo, at which point law enforcement had no choice but to act on it.
The point is, when Gizmodo wrote about the prototype iPhone in their possession, as far as they knew it was a hoax since Apple denied the existence of such prototype, so Gizmodo can't really be charged as an accessory to this 'theft'.
I get the fact that Apple may be concerned about files on Gizmodo's computers which may show the inner components of the phone, and that is something they can request to have returned, but it should have been done through a legal injunction and not through police force. Apple definitely overstepped their bounds on this one, but it remains to be seen how much they'll be affected by this bad PR in any event. I suspect people will still flock to purchase their products because the Apple image stopped being about 'bucking the system' a long, long time ago.