It is now becoming clear that people are using the TP as a trash can.
per:
http://www.reddit.com/r/Guildwars2/comments/10g6m6/do_people_completely_ignore_the_tp_listing_fee/
My suggestion is as follows.
At day 15 that they have an item in the TP. They are sent an email saying they have an item that has been listed for a long time.
Suggest in this email that they remove the item and re-list it or just remove it all together.
If they do not remove the item then on the 20th day. Have it setup to either destroy the item or sent it to the player.
At the same time charge the player for the cost of the item if they would have sold it to a vendor.
Selling to vendor gives them 20 copper for example.
they do not remove it. On the 20th day have 20 copper removed from their money.
Warriors are those who choose to stand between their enemy and all that he loves or hold sacred