Ilan Strasser of Fat Moose Comics and Games of Fat Moose Comics and Games in Whippany, New Jersey saw the comment by Jerry Ringi of Amazing Fantasy Comics on comic street dates ('Jerry Ringi of Amazing Fantasy Comics on Street Dates') and notes that enforcement issues have been a sticking point in the past:

Jerry, as a retailer for 10 years longer than you, let me wish you good luck in your endeavor.  However, Diamond has repeatedly turned down any and all requests for street dates because simply put, they don't want to pay and maintain what they call a 'police force' to make sure that we retailers don't break the street dates.

Diamond will tell you that it isn't so much the cost, but that the logistics of policing and enforcing the street dates is what constitutes the most difficulty for them.  In my mind, the reality is that aside from the valiant efforts of many dedicated and hard-working customer service reps who often do the very best they can under difficult circumstances, Diamond is no better than Marvel & DC -- the two big guns whose policies and protocols decide the future of the industry.

What I learned long ago that no matter what the outreach says, we retailers have rarely, if ever, been partners in this industry.  We have survived in spite of the publishers and distributors and the truth of this is in the fact that so many mass-market retailers fail miserably when they try to sell the products we have blazed the way with.