This is all well and good (and a little silly) but as a former pizza delivery guy, I can see a few pitfalls.
For one thing, are they giving the poor drivers the advantage of the GPS system, as well? It's great to see your pies streaking towards their goal, but watching your pizzas circle the block for the fifth time, looking for your address... that can't be good for business. This is compounded by the fact that a lot of the databases we base our mapping on are terribly innacurate. All the major mapping systems put my boss's house on the wrong side of the lake, for example.
So, perhaps, we need to ditch the navigation systems, and just go with raw GPS data, a la geocaching. Please deliver my pizzas to 41°13'36.62" North, 85°49'28.04" West.
Payment and tip are at 41°13'36.74" North, 85°49'36.11" West...
Always tip the delivery guy, by the way. Especially if you make him swim for it.