The gate looked locked. It would be even more stupid if he "checked" to see if the gate was locked with a lock right on the gate staring him in the face. And I'll bet his buddies haven't let him live that down yet... 
I was just taking the piss, and you're right, his police mates probably watch it on you-tube all the time and razz him up. It is very funny though, I laugh every time I watch it.