There are a lot of iOS apps in the iTunes Store that, upon launch, check the device's UDID and other info and setup a mail compose interface so your would-be beta testers can conveniently send you their UDIDs without all the iTunes hassle (e.g., can't copy/paste UDID in iTunes app, only in Xcode). For example, this one by Erica Sadun: http://itunes.apple.com/us/app/ad-hoc-helper/id285691333?mt=8
I am very aware that the UDID was deprecated some time ago and Apple has begun rejecting apps that use the deprecated API. But I would also like to make my own custom "Check your UDID and send it to me via e-mail" app, if anything because it looks more professional (and feels safer) than redirecting my potential beta testers to a third-party app made by someone else. (No offense to Erica!)
I guess what I want is not possible anymore...? Any thoughts, experiences to share?
*Also, I am not planning to use services like Test Flight at the moment (perhaps some day).
What I think is apps that currently get the device identifier and use it somehow, won't be banned. The property uniqueIdentifier of UIDevice is depreciated in iOS5.0 so as long as you check you're on system with iOS5.0+ and don't use this property everything would be fine. What Apple suggest is
Special Considerations
Do not use the uniqueIdentifier property. To create a unique identifier specific to your app, you can call the CFUUIDCreate function to create a UUID, and write it to the defaults database using the NSUserDefaults class.