Just curious, but if snow can get in there then so can water from a rain storm correct? If that is the case and logic then you should cover it when it rains as well. Sorry I just don't see the logic or you should cover the AC unit, furnace and water heater as well. We get wicked winds and blizzards and I have not seen any accumulation inside any of those places. As has been said above though, it won't hurt but is just something else you must document to remember to do in the spring.
John & Deb
2011 F250 Lariat FX4 Crew Cab 6.2
2011 Flagstaff V-Lite 30WRLS
Days Camped 2013: 16 2014: 5 2015: 3