An onmi-directional sensor would probably work fine. I have not seen them at the 'home centers.' I have used them in offices, where they are actually "occupancy sensors," and operated using different technology than your plain-jane motion sensor. I had not considered them because of the 10x or greater expense. Pardon the pun, but they were just 'off my radar.'
The application is an ordinary carport - meaning there are two distinct ways you can approach: either by coming up the drive, or by exiting the kitchen door (on the side, up front, in the carport). Since Harriet Homeowner wants the light to come on as she drived into the carport after work, and wants it to come on as she exits the kitchen on her way to work in the morning, there's a need to sense in both directions.
Security? This isn't Ft. Knox. It's all about convenience. We also don't need the light coming on for every passerby on the sidewalk, or every rabbit that crosses the back yard.
Run additional pipe, and locate the sensor where it will cover both approaches? That might be possible. I had not considered that- though that location has other issues.
