One important thing that I forgot to mention about the MBA...it takes a LONG time (3-4 hours) to fully charge up the battery. This is a big handicap you may get if you go with the MBA. The new battery in MBP is years ahead of the one in MBA, in terms of the technology it uses
You make a good point, the newer MBPs battery charges sooooo much faster then both the older MBP and MBA. In a situation when access to power was intermittent and limited it might be an important advantage.
You buy the retail copy of OSX so you did pay for it. You do not modify any source code when you install it...
edit: *points to your sig* You have a Mini9 with OSX?
Anyway as a MBA owner I agree that you probably won't want to use it in the field. You are more than welcome to try however, might give me more confidence about my MBA. But from my experience a MSI Wind will take more abuse than the MBA.
There is really no point in correcting someone who doesnt understand the legal definition of theft or the difference between civil and criminal!