Sunfish, I dont see anything in the fishing regs, but I suspect it comes under other laws.. maybe something as simple as littering or illegal dumping. It could be considered polluting the lake.
 
It's a grey area in my mind, as one could say the trees used to mark trails in the winter fall in as well, and fall under the same laws/rules?. But if you're able to get away with a tree, then where do you draw the line? obviously somethign like a car is on the other side of the allowable line. Not sure how they would differentiate what's acceptable, it anything.
 
Not much help, but err on the side of caution is my advise (and be mindful of what goes into the water!!)
 
regards, Mike.