Hell, one day I had an altercation with a motorist in the bike lane and called the police. The cop showed up... and parked in the bike lane. That I had called the police to keep cars out of.
(I'm proud to say that bike lane has those flimsy plastic sticks "protecting" it now, though.)
One day I called out a cop for this in my hometown. His explanation was that if they get an emergency call when they're inside, they don't waste time getting back to their car.
It's really not. If that's the case, then they shouldn't be allowed to go into the coffee shop while on shift, they have to go through the drive thru. If they are taking work break, then they need to have coverage, just like other jobs!
The drive thru is worse. Their crusier could get stuck in the drive thru between other cars, the building and the curb. Even if people did move out of the way while they are in drive thru (some people will still try to get their coffee first), it would completely mess up the order of the drive thru orders.
A lot of things can save time in a hypothetical situation. Where do you draw the line? Parking? Property damage? Why don't we draw the line at not doing illegal things, no matter how inconspicuous.
Parking illegally can also hinder people from getting help from an ambulance or fire truck.