But then they also need to download other large files regularly. So I think their policy is to tell people to do it over wifi, and most people can do that, beca

But then they also need to download other large files regularly. So I think their policy is to tell people to do it over wifi, and most people can do that, because their car sits in a garage or near a house all night. Seems sensible, no? Why take the risk of messing about with deltas when most customers manage fine.