I'll add one more thing that might make it the line more understandable.
Years ago in NY people would often call for a 'cabbie' instead of calling 'taxi' when they hailed. And if you were standing next to your cab on the street chatting with another 'cabbie' which people often did then in a taxi line, the person hailing you would call you 'cabbie' just as you might call 'waiter' to get a waitstaff member's attention in a restaurant.
So for a TAILOR to mistake you for a cabbie would mean you would be really dressed badly or dressed down or that your clothes were a mess.
"Life is a lesson in humility"