In the US Army, they'd make us pose for shoots like this after something we jokingly called "Mandatory Fun". You can come to this totally optional event to prom

In the US Army, they'd make us pose for shoots like this after something we jokingly called "Mandatory Fun". You can come to this totally optional event to promote $SOMETHING this weekend, and if you do, you get the day off Monday. If you don't, you get to scrub the halls, wax the floors, and inspect the vehicles at the motorpool. It was optional "technically", but mandatory in reality.