The question is a joke, the reason is dead serious!
Why asking for avoidance of all Mountain area's by default in BaseCamp?
Well, because all zumo's models 310/340/350/390, 590 and still also the BMW Navigator V all loose their way in the Mountains. Not everyone seems to have problems, but there are several stories in the Netherlands and Germany of people who have zumo devices which loose there way in the mountains, project itself far from the road.
The problem exist already 2 years now, for the BM Navigator V there is an update, but it's not solved completely. Information is available at Garmin, lots of people have send additional information to Customer Support.
So because our zumo's don't support driving in the mountains, why give the possibility to plan routes there ;)
Garmin! We are waiting! Please solve this a.s.a.p. At my location the winter is started, but at the other half of this world spring is beginning.
(Garmin wants to be the best company in navigation? Please show us!)