Property owners have a duty to ensure their premises do not present a danger to guests.
If the property owner knows of a dangerous condition and fails to correct it or warn guests, the owner is negligent and responsible for the resulting damages. For example, a hole or uneven pavement that is not readily apparent to the guest constitutes blame. Having a swimming pool or other dangerous attraction that is not fenced off is another example.
In a specific case, a business parking lot had a large area of slime where customers parked, a man slipped, fell, and broke his hip. The evidence in the case established that the slime had been there for years, the owner knew about it, and failed to address the problem. Needless to say, the case was successfully settled.