Ask him if that is what he would do if it was his car, and he was paying out of pocket. If the answer is yes, I'd do it. Bumpers are there to be bumped before the rest of the car anyway. If you lived in the city and parked in the street, after a couple years your bumper would look like hell. This kind of thing happens all the time parking in tight spots.
I'd do it that way for no other reason than the fact that you wouldn't need to hit up "dumbass" for quite so much money, no doubt, a bunch of money he might rather not part with. Neither of you will feel so bad about the whole incident after it's done.
You are right that bumpers are meant to be bumped, and heck, I live in NY, and I know the likelihood is high that it'll happen again. I already know that the guy from the shop prob. wouldn't bother doing it, just cuz the damage isn't that major. However, what are my other options? Tell him to give me $5 for touchup paint and I just do it myself, tho' it'll still be visible? Tell him not to bother, and that scratching my car while he was definitely driving drunk is ok?
To me, this cost is reasonable, if just for the fact that the other quotes I heard were like $400+ for a full bumper re-paint, a price I couldn't fathom telling someone to pay for a few scratches.