I too have used Slice for every stay. I have never had them decline coverage and I have never had to file a claim.
I did check into Proper and they declined to cover my completely renovated 1953 home because the main sewer line from the street into the house was cast iron. All plumbing inside the house connecting into that line had been replaced, but that wasn't good enough for them. I do most of my remodel work myself, (which is completely legal as a homeowner) but they also required verification from an electrician and plumber that the work had been done and was up to code before they could cover my home.
Hope you have better luck or a newer house 🙂
Merlyn