I'm not sure about the issue with the house or flat thing but if it's a red flag to you, it's a red flag. Personally I just think it's a bloody stupid and unnecessary question. Flat or hotel fair enough.
Regarding days and nights, I've never worked nights while indie as I only work from hotels now, but I did work until 2am with my old agency. I never found that anyone was more dangerous at night, In fact I barred more people during the day. I did get a high volume of drunk and coked up clients at night, but I mainly worked late on weekends so that may be why. They wouldn't pass my screening now but I didn't find them a massive issue, they were actually more generous than day time clients and more often than not, extended.