It's too big, however I have it encased in an Otterbox case which is bulky. I leave mine on the table charging until I return. I've left more valuable things in the room without ever having anything stolen. You may be better off locking it in your suitcase if you're worried about it.
We just got back from POR Riverside, and the safe is not big. Trying to recall if the safe from the Wilderness Lodge,where we've stayed before, was any bigger, but I don't believe so.
We just got back from POFQ this past Sunday and we put our Ipad in the safe with no problem. Also, took it with us on our Dec 2010 trip and it fit in the safe at the Poly. Two different sized safes.
I have the original iPad w/ otterbox case and was able to put in the safe at both Coronado Springs and at Wilderness Lodge, along with wallet, iPod etc.
My 3rd gen iPad in a case and a sleeve fit into the wall safe at All-Star Sports with a little room to spare for my wallet. I don't think any generation of the iPad, or any similarly sized tablets, would have a problem fitting. More than one might be a problem.
I think it depends on the resort. We stayed at Kidani earlier this month and easily fit 3 iPads (2nd gen) in the safe. There was plenty of room for our other valuables, too.