As a result of going to Subway too many times and taking lots of online feedback surveys in a short burst, I accidentally noticed the pattern of Subway’s validation code you put down on a receipt after taking an online survey, which allows you to redeem a free cookie the next time you visit Subway.
The pattern is actually quite simple:
(Average Survey Score)-(Store Number)-(Date)-(Time)
For example, given the following information on the receipt:
The store number is 38023-0.
The date is 04/17.
The time is 12:47.
If I choose 10 for all items on the survey form, the average score will be 10.
Then, the corresponding validation code would be 10-38023-0-0417-1247.