Ack I could name a number of times where I did this..and then there were times where my gameboy's light turned red which meant it had to be charged and I was in a battle..or even when both my Pokemon fainted in a double wild Pokemon battle in my Pokemon White..and I couldn't sent out another Pokemon because it wouldn't let me so I felt I had to turn it off..and even once when I was in a rush for something..so yep it has happened to me.

I needed to do something quickly
I ko'd my current target
I got bored
Rather not lose money after being beat
Wanted to undo an evolution

i sometimes in a rush and other times i loose a battle and all my money just turn it off.So next time dont battle that person again..XD

ANIME IMAGE (EXCEPT KECLEON) YOU USE, MCHOPNPOP!

once i beatthe poke leage it didnt save yet then im like H O L Y F U C K I N S H I T!!!!!!!!!!!!!!!!!!!!!!!!!

well, yes, sometimes i turn it off for undoing an evolution, or when i lose in a battle or when i catch a pokemon i already have, and sometimes i turn it off by accident.

Yeah... Annoying during shiny hunts... So I save my game regularly, in case I somehow forgot and I managed to get a shiny.