Negligent security is when a hotel fails to provide reasonably adequate security for patrons which, in this case, results in a sexual assault. This can include things like failure to provide adequate lighting, secure access points, properly trained staff, and functioning locks on hotel room doors.
Determining negligence requires proving that the hotel had a duty of care — a legal obligation to provide reasonable security — which they failed to uphold. It must then be shown that this failure caused or contributed to the sexual assault, and that the victim suffered actual damages as a result of the negligence. Negligence is ultimately determined by the judge or jury in the case.