Could have been just placed there by the prop guy (it looks good next to everything else) or recommended by a consultant (this is the mobile device of choice).

Exactly. Usually when a script calls for some fancy-lad handheld electronic gadget, they turn to the prop master. Prop masters by the very definition of their jobs are usually jack-of-all-trades geeks since they usually wind up having to modify a prop to suit the director's vision. And since there are usually one or two hardcore geeks on the set at any given moment, if the word goes through the film crew on suggestions what to use for a electronic prop, those folks usually know what best to use.
The few times I've been on a set in my life I saw no end of portable gadgets being used by everyone. Seemed like everyone had a damn Crackberry or Treo with a ton of Nokia smartphones as well. "I'll get that right to you" usually meant "I'll email it to you from my laptop or cell phone".
For all the technology and terminology Hollywood has gotten wrong and flat-out corrupted in the past (Damn you "Hackers"!) in the real world they are pretty tech-savvy.
Even Bruce WIllis reads news and does video chats with fans on the internet. Using a Mac no less.