I guess the connection is that when you're far away from home you can project an aura of confidence/respectability that you may not have at home where people know you since the days you were not yet an expert.

Of course people can't be born experts and for every expert there must be a prior step in their personal growth when they were less expert. But that doesn't prevent people from using an imperfect heuristic for judging whether you can trust someone's expertise.