Very few manufacturers schedules require headlamp or wheel alignment checks and unless a car is under a manufacturers warranty then you have no particular reason to apply the manufacturers spec anyway. There can be things like checking fault codes that are often listed on the manufacturers spec that could be a difficulty for all garages (on, say, a Daewoo) so I don't see it as an issue that applies particularly to mobiles.
For myself I do mostly diagnostic but some service and light mechanical work and I dispose of waste fluids via some of my trade customers who use me for diagnostics but would admit that the ability to cut down the bulls##t factor that modern legislation brings is generally a welcome benefit of working mobile.
Bottom line, I think, is that you can professional from the back of a van or at a workshop, or you can be a cowboy, I'm simply hoping that this new legislation will only go after the cowboys.