Yeah, I thought the shoe recognition thing was kind of funky, too. If they had been combat boots, it would have made a lot more sense. Maybe it was that the shoes weren't black and 'regulation' appearing.
shareThe shoes were not the point..a postman never follows you inside!
shareThen they screwed up because the camera perspective made it 'look' like the shoes were the point.
If they had used shoes much more typical of what a mailman would wear (black, oxford types), it would have been clearer that they were trying to show that a postman never follows you inside.
The mailman's shoes in the movie simply didn't look like something a mailman would wear, but not to the extent that they would have tipped off Turner.
What about the mail mans shoes made condor suspicious?