Sure, apparently the old glitch where you could remove the cartridge while a pokemon was being sent to the GTS still works, you just have to be very precise because if you remove it too early then the pokemon won't be sent to the GTS, and if you take too long then it won't be in your PC anymore.
Be warned, same as before this is incredibly risky. Although the game creates a backup of your save, but still.
And this doesn't work with digital copies for obvious reasons.
Also keep in mind that I haven't been able to corroborate this first-hand because I don't have a retail version so it might not be true.