Remote access of an iPad display from another iPad
Solution 1:
The iOS security sandbox will prevent any App store app from sharing the screen of any other app on a stock iPad. However the built-in AirPlay mirroring will allow a user to send a mirror of their iPad display to an Apple TV.
Solution 2:
A clunky workaround would be to have the client take a screenshot and email or iMessage it to you. Screenshots are taken by pressing the home and sleep buttons at the same time until the screen flashes and you hear the camera noise. The screenshot is saved to your Camera Roll.