I've used hotel sitters in several European countries and the US. I have no issue with it and obviously if I were concerned or had a bad feeling about the sitter or situation I wouldn't go. It's been totally fine. I felt more comfortable about using a sitter through a hotel or agency (have done both) because there is some accountability through them, and generally some background vetting that I cannot do as a foreigner in a different country. Each time the sitter has remained at the hotel with the kids, usually in the room and simply fed them and put them to bed.

We lived in Europe for six years and several times left my daughter with a sitter at our hotel. Most hotels either use an agency or have a roster of sitters they have used regularly and have a relationship with. All the sitters we used spoke English which was our only requirement so they could communicate with our daughter. We never had any problems. I don't see how using a hotel sitter in Europe is any different than using one in the US, which we have also done.

I did it in France with a sitter our apartment rental agency found for us. They had standing arrangements with a few people and I was told she also sat for the agency owner's children. We used three times during a 10 day trip for lunch dates that occurred during nap time. No issues at all.

I have done this several times. No problems.