[mario]

It's eBay that enforces these rules, not Gixen. Below is a more detailed message as received by eBay:

Dear Buyer

To prevent the circumvention of the http://pages.ebay.co.uk/help/policies/weapons.html eBay.co.uk and http://pages.ebay.ie/help/policies/weapons.html eBay.ie Weapon and Knives policy, it is not possible for you to bid on, or buy this item.