"I would hope any other store holders would understand the ramifications of high numbers of GTC listings, especially when the terms of the offer explicitly state what they are."

You and I understand the ramifications but free GTC listings could on the face of things imply free rollover to some.

An internet dysfunction during a crucial period could cost some dearly.

The free GTC listing should not have been made available during the promo, only a 30 day listing as max

unless of course I am failing to see the advantage of a GTC listing that is only free for 30 days.