Trolling for rapid advancement? [ Edited ]

[JedTheRealFish]

If you have a monitor searching for players rapidly climbing up the ranks, just so you can strongarm your way into a battle with them with a perfect draw, please remember:

On tablets, it's quite easy to take a screen shot just prior to the battle, as I did with ultimate league player LANgyuen, who is not registered. That is, when invited to a battle, the system says "player not found."

I am wondering how this is possible?