It is not uncommon for boaters in the frozen winter tundras, of say, Minnesota and Wisconsin to bubble their boats in the water over the winters. But, they do it in marinas that are set up for this. By being set up, this means, the marina provides the bubblers (one of the best bubblers on the market was created in a small river town called Afton, MN) and they have staff all winter to monitor their function. So, if there is a power failure, or similar problems, they catch it daily and can deal with it. They also shrink wrap or cover the boats so that there is a ridge pole high enough to send snow into the water and not have it pile up on the boat. I can't imagine someone putting a boat in the water all winter where it snows 4' and not cover the boat. 4' ain't nuthin' when it comes to winters in MN or WI, by the way. Also, the docks where the boats are bubbled in are maintained by the marina staff who keeps them clear of snow so you can get to your boat (or they can get to your boat). Obviously the boat has to be winterized and also seacocks have to be winterized. I have seen seacocks freeze up, burst and sink boats. If done properly, there is not problem. Also, people are requested to not have heaters going on in their boats when not in attendance. This can be a cause of fires. So.....bubbling in boats is something that is done regularly in climates, but there is a system and safeguards.
There is one marina in St. Paul, MN that has a number of houseboats that remain in the water all winter and people live on them. They bubble the boats in as described and then they cake the boats up on the outside with blocks of foam and then envelope it all in plastic. But, it is done because the marina allows it and tends to them. Go south where it was frigid in Florida, but no frozen water last winter.