We don't worry about it. Over a long weekend, we'll get a little frost built up, but it doesn't hurt anything. When I get home and cut the fridge off, I just mop up the water out of the bottom of the freezer compartment and end up with one very wet kitchen towel, so it's not that much water.
I've read other users will cycle the fridge every day to keep ice from forming? I've never had enough ice buildup to worry about it, so I've never looked into it.
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!