What Keg said....
And furthermore: IF, IF, IF something in the cockpit starts to go haywire, such as a VNAV display discrepancy, or a LOC or G/S indicator bouncing around, or a VOR needle flickering on and off, AND the pilots suspect the powered-up iPad might be a factor, we can immediately turn them off. That's not so easy to do if it's possibly attributable to the 200 iPads powered up down the back.
Then again, all the things in the last paragraph happen now and then anyway, so we probably wouldn't attribute it to the iPad!
Genxfrog: the problem is, I hear people with your attitude all the time: "Why should the pilots be allowed use iPads/laptops/cameras/(insert electronic device here) when the passengers can't?" It really becomes an "us vs them" thing! They and you simply don't get it. We are IN CONTROL of the aircraft, you are not. Yes, you are the customer, you are important, you are "the reason we fly", but if there are config/compatibility issues with electronic devices we need to be in a position to fix/control the problem. Allowing unrestricted electronic device use by pax doesn't allow that. Electronic devices on the flight-deck, however: no drama. Can be turned off immediately if an issue.
I personally think the whole portable electronic device thing in aircraft is grossly overstated but I'm only the Captain, what would I know, so until the boffins get their act together in about 100 years and declare them safe then that's just life!
Hey - you have one over us pesky pilots: we cannot use Bluetooth devices in the cockpit at any time, but you can in the cabin. Happy?
Don't worry, I won't be checking my email on the iPad as I land. I'll do it in the turnaround over a quick coffee!