I think this subject can just go on and on as there are so many permutations, We all use our iPads in different ways, different apps and use different web sites, After my experiences i really think in almost every case this is going to be a software issue, I had two Airs in three weeks both doing exactly the same thing and if i had taken Apples advice i would have had three and i'm pretty sure the third one would have had the same behaviour.