Is the Heating of New IPad a defect or not?

Recently bought an Aqua case for a new Ipad 3, the case being dust proof and water tight. Case manufacturer promo said the case was suitable for indoor use to protect from dust and other polution. I bought this case to use on a boat not because of the risk of water ingress, but to give good protection if the Ipad was to slip off a table.

I used the Ipad in case for marine navigation with the turn off setting set to 'Never'. After 45 minutes I noticed the Ipad had switched off, when powering on therer was a message on screen saying the Ipad had turned off due to excessive heat. When opening the case and removing the Ipad I could not hold the unit as it was so hot, the case being scorched and damaged. I reported this problem to the case distributor who was made a record of our conversation and gave an immediate refund.

Fortunately the Ipad appears to have survived unscathed, where I was expecting the worst.

There is a problem with excessive heat that must be known. Ipad 3 should never be placed in an air tight/water tight case as the consequences are dire as it definately needs exposure to air to aid cooling, although I am sure the case would work correctly if submerged in water. When looking for an alternative case it seems many cases are constructed from soft or hard plastic close fitting to the body of the Ipad and restricting necessary air flow for cooling. Unsure whether any case is suitable. Apple should give a warning relating to application or unsuitable cases, case manufacturers need to test and evaluate their products with the Ipad 3 prior to marketing their products. I consider myself lucky, this problem needs to be addressed. Apple will say 'Not their problem' as the cases are produced by others, but buyer beware, I believe the Ipad 3 does have have serious heat issues.