So yesterday I heard about this alternate way to get in to the Station as the main access point was boarded up. When one of my friends climbed through, he saw what he thought was a sensor, but we didn't know whether it was on or off. So we decided to deliberately set off the sensor and see if it did anything. When we waved at the sensor, it made no noise, but we left the premises to be safe. 20 minutes later we saw a Community Patrol van pull into the Police Station and a second one not too long after. They were in there for a good hour before we decided to call it a day. Does this sound like the sensor was working? Or that they were just checking the premises coincidentally as we were there?