The message
from "Mary Fisher" contains these words:

You can adjust/mask the sensor so it only goes off when you want it to.

Loses the point, really!

No it doesn't. We've a PIR by the front door, but unmasked it reacts to
people walking along the footpath outside. Masked it only lights as you
walk through the gate.

--
Skipweasel
Pay no attention to that man behind the curtain.