I've used ADCO type RV covers on several different RVs in the past and there has never been an issue. You do have to watch those buckles and other rub points. Moisture was never a problem either in middle TN or in FL. I now have an RV port so I no longer use a cover.
ADCO covers are pretty breathable. Now if you're talking about a cheap plastic tarp type cover I imagine that's a different story.
When seconds count, the police are only minutes away.
2019 Newmar Canyon Star 3627 on a 2018 F-53 26K chassis w/6 speed transmission
2017 Jeep Wrangler JKU with Ready Brute tow system w/Currie Tow Plate
Titusville, FL when not on the road