Pete: There's lots of literature out there on the subject. Hitler hated the Swiss but in a rare moment of lucidity, realized there was nothing to gain by an invasion. The Swiss were taking care of them under the table and the Germans took care of them by placing billions in currency, gold etc in their banks. It was a great conduit for espionage dispersion into other countries (so was Sweden) etc. But to the OP, had the Germans wanted, they could have crushed the Swiss.
Don't forget Spain...lots of espionage operated out of Spain. Spain provided friendly ports for the Germans. And from Spain the Nazi's sent spies first to South America (Argentina and Brazil), then on up the continent. Germans had a lot more allies than we were taught in school. Just very few were "official" above board allies, remaining "technically neutral".
