Photo Radar Trap

An off-duty police officer, familiar with radar guns, 
drove through a school zone within the legal speed limit 
when the flash of a camera went off, taking a picture of 
his license plate.  

The officer, thinking the radar was in error, drove by again;
even more slowly.  Another flash.  He did it again for a third 
time, at an even slower speed.  Same result.  

"This guy must have screwed up the settings," the off-duty 
officer thought. 

A few weeks later, when he received the violations in the mail, he
discovered three traffic tickets: each for not wearing a seat belt!