iPad and cruising
I just returned from a cruise yesterday and security at the terminal asked me to remove the iPad from my carry-on during the embarkation process at the begining of the week. It was in a CIMO TPU case inside of a small netbook Incase. It wasn't a problem, though.
By the way, the Wi-Fi worked really well at the ship's various hotspots. We were on Royal Caribbean and used the cheapest wi-fi package to quickly check email, etc. Setup was very easy.
Just returned from Hawaii, and was not required to takeipad out of it's belkin sleeve when going thru security.
Used it poolside for most of the trip with only 2 overheat warnings.
You should be alright leaving it in your bag.