I guess it depends on where the dealer is and how secure the lot is (and how honest the employees are). No way I'm dragging all our stuff out, finding a spot for it, then dragging it all back in. We had ours in to the dealer last month. I thought it might drag on waiting for warranty approval and then a part, but it was done in 2 weeks. Other than in a cabinet where they had to fix a leak, we didn't take anything out. No problems.
But for sure, anything very expensive or irreplaceable - take out. Most of the dishes and stuff we have in the camper are either old ones we replaced in the house, or inexpensive stuff, so we figured not a lot of risk.
2005 F-150 FX4
2013 Rockwood Roo 23 IKSS