When the window alarms on your van go off

JaneandIan

So here I was, happily ensconced in the motorhome, pitched at a very empty and quite isolated but much loved CL when the window alarm goes off, albeit briefly. It scared the living daylights out of me. I switched the lights off and lifted the blinds one
at a time but all windows are firmly closed. Still a bit spooked. Has this happened to anyone? What did you do?