Yes I would see risks in doing that.
Thats just a ton of stress to put on an already depleted body that does not have its typical natural defenses and is already prone to cold with unsustainable unhealthy bodyfat levels.
Could send a signal to the brain to use any energy for fat and might also make you hold water aswell.
Just can't see how it could help.
But on the flip side never heard of anyone doing it close to a show and it could have the exact opposite effect I what I think. Would certainly be interesting to hear the results if you do give it a shot.
If you haven't done it a few times before and know exactly how your body is gonna respond then I would NOT advise it.
Everybody responds different to things like that , it could make you hold water , drop water and who knows what else.