It just turns into a mess. Line freezing in the guides and snapping, the water freezing up and messing with electronics, lithium batteries + the cold can lead to issues and then people are getting towed in. It would be a challenge but could also get really expensive. The last really cold tournament I fished I also had a rod basically explode in my hand on a hookset and had to get graphite/carbon fiber splinters taken out of my hand at urgent care.