I was at my local McDonalds the other day-
http://maps.google.com/maps?f=q&hl=en&geocode=&q=s.+westnedge+49024&ie=UTF8&ll=42.216623,-85.588646&spn=0.001222,0.002151&t=h&z=19

Take a look at the satellite picture- see the handicap spaces on the left side of the building? On the "Bottom Left" of the building, right before the DT, I saw what appeared to be a service door. So if the truck was unloading with the back pointed towards this door, then therefore the handicap spaced would be blocked.

I personally think that Mcdonald's needs to come up with some sort of procedure as not to disturb the handicap parking area.