Yeah, it is cheese, but could you catch a mouse with it?
I dont even think this should be corrected. Yeah, it probably should be till end of encounter, but so what? Either the DM will allow it and just take it into account when playing, or the DM will convince the players that abusing the rules is a bad idea. Can you say 'Wandering Monsters'?
Quite frankly, the second option is a far better way to take care of the situation.