they are put on by template.
there is a plastic 'tool' that is used basically a piece of plastic with the Z4 logo and a hole for the turn signal indicator that goes all the way to the end of the fender. They place the plastic on over the indicator/emblem, push the other tip into the seem between the fender (wing) and door panel, which ensures it is level, then press down. They pull off the template and the 'plastic' stuck on the top of the emblem.
The one on the trunk (boot) lid is similar where it lines it up with the top of the trunk and turn signal.
They are obviously put on by hand, not by machine.