Well on the devil's advocate side of the argument - if you don't know why your patch might fail, it's going to be difficult to guarantee a way to back it off. Chances are that the factor that caused the patch to fail will also be the thing getting in your way when trying to unapply the patch.
That's unfortunately a difficulty intrinsic in any open system (too many variations to make something 100% foolproof).
----------------------------------------------------------------------------------
Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?