you can avoid this fuss about actually changing your mac address - all
you need to do is change the mac address as seen by the application by
overiding the relevant library call, eg:
http://www.chiark.greenend.org.uk/~peterb/linux/fakeif/

of course i don't endorse any of this sort of behaviour but have used
something similar in the past. once you've faked your mac you might
as well go ahead and fake the date too so your licence won't expire and
then you can fake your gps position to save on fuel costs.

btw, does anyone know how wayfinder know which licence trial region
you get? is it based on whichever map is active at the time? or
your gps fix? maybe someone with some unlimited licence magic can let
us know.