Like others said,
For alcohol, makes you a cop magnet - do you ever have a beer after work?
Sounds low for the "use of a rolling billboard"
If you do get this, get it in writing that it will be paid in the form of per diem, but there may be a limit (1year?) that you could do that. That makes it tax free.
That being said, if Stihl or Snap On wanted to wrap my vehicles and I got paint protection for XX months I may consider it. Better yet let them wrap the wife's minivan...