Motion detectors

The light switch in a public bathroom in a 24-hr. grocery store is controlled by a motion detector and hooked up to a timer. When someone walks in, the detector turns on the light. The bathroom is housed in a large room. The motion detector is located by the door, but the business end of the bathroom is a fair distance away, on the opposite end of the room. At 7:00 a.m., the foot traffic in the bathroom is very light, and if a person spends a while on the useful end of the bathroom, the timer does not realize there is someone there, and turns off the light. No amount of hand waving can then turn it back on. They don't teach that in engineering school, do they?