Even back then if you were paying cash, the room rate was paid up front. Any incidentals like food or beverage were paid at check out to avoid skipping out on the whole bill. Back in the late 80s and early 90s I traveled to Europe a few times and you sent cheques to smaller establishments like B&Bs or provided your credit card details over the phone to larger hotels like this on. She must have stated when she made the reservation she was paying cash listed. If they didnt collect when she checked in it may mean they were familiar with her or they were really busy. I can't say she paid the room rental on arrival because that hasn't been established to my knowledge. If they were concerned only about room service, one meal and several soft drinks I can't see sending security up for that.