(Using US examples in the following, because probably the majority of the readers understand it better than European cities, even though it does not apply to the US).
Say you are living in NYC where your company is based. Every day you get an email telling you where you have to install a new security system. One day it might be Brooklyn, one day it might be Washinton D.C, because everything is being managed from the central NYC office.
Why exactly should traveling to and between the appointment (say Newark in the morning, Bronx in the evening) not be considered work? The employee is not living 4 hours away from the first appointment because he wants to own a bigger house, but because his employer has told him to work there.