Fifty violations of comic street dates were detected by the secret shopper program run by Diamond Comic Distributors in 2013, a Diamond spokesperson told ICv2 in response to an inquiry. On a percentage basis, assuming each store is visited at least once a year, this is roughly consistent with the 98% compliance rate Diamond discovered the first month it ran the program, back in 2011 (see "Diamond Finds 98% Compliance with Street Dates
The use of a secret shopper program to monitor compliance to comic street dates was implemented when the Day-Early Delivery program, by which Diamond delivers comics to retail stores the day before they are to be put on sale, was launched (see "Diamond Details Day Early Delivery
It’s surprising that despite the knowledge that compliance is being monitored (retailers are charged $4 a week to participate in the Day-Early Delivery program, to cover the costs of the monitoring), and after years of enforcement with sanctions for violating the street date, retailers continue to violate street dates in roughly the same percentage.
Sanctions range from one month to three month suspensions of Day-Early Delivery service, or in the casee of a three-time violator, a permanent ejection from the program.