After all, considering the number of times Jim and co appeared in the media all over the world as part of their covers, somebody on the other side should have noticed the same white-haired guy constantly popping up under different names...
TV shows back then didn't have the same approach to continuity that most shows today do. The favored dramatic form was the anthology, since the classiest early shows had been the showcases that did different plays (adapted or original) every week, whereas serialization was limited mainly to less respectable stuff like soap operas. So even a lot of series with continuing characters were structured like anthologies; there was often a quite deliberate avoidance of continuity from one episode to the next. So even though there were all those episodes where the team members exposed their faces to the world, they were still able to keep going unrecognized week after week. It was more as if each episode represented a different parallel timeline than adding up to a continuing timeline.