I actually made this mistake yesterday by submitting a meme to the Fun stream (was meant to go to Politics), i waited for it to be rejected, but the Mods accepted it and featured it in fun under NSFW, but it wasn't a fun meme.
WHEN SUBMITTING A MEME
IMGFLIP SHOULD GIVE THE CREATOR THE ABILITY,
FOR A LIMITED TIME, TO RETRACT THE MEME
JUST IN CASE THEY SUBMITTED IT TO THE WRONG STREAM; INSTEAD OF HAVING THEM WAIT HOURS
FOR THE MEME TO BE REJECTED
SO THAT THEY CAN POST IT IN THE CORRECT STREAM