Keep a counter on each shopkeeper representing the number of times a pet has picked up a shop-owned item in their shop (or a shop-owned item inside containers they are carrying). Every time this increments, use it as an increasing chance that the shopkeeper will become aggressive towards pets picking up their wares, with messages like “Kabalebo shouts “Hey! Drop that!” at Fluffy. Fluffy drops [item].” Once they are past that point, you can’t use pets to take their items anymore.

The point on the counter at which the shopkeeper stops playing nice should be roughly some fraction of the area of the shop, to strike a balance between large shopkeepers being more lenient and not allowing you to clean out all the tiny shops in Minetown. A rumor could be added for this: “They say that mom-and-pop stores have lower tolerance for thieves.”

Unspecified whether the counter should increment when a non-pet picks up an item in the shop. Probably not, since this is a fairly rare case.

Make shopkeepers more susceptible to being paralyzed or put to sleep than they currently are, so it is easier to directly but non-lethally steal from them.

After a pet removes a shop-owned item from a shop 5 times, the shopkeeper stops permitting pets in the shop.

Shopkeepers remember when you have robbed their shop even after you pacify them, including in a bones file with a player of the same name who had robbed the shop. They treat former robbers as suspect, and enforce stricter rules on them and/or raise prices for them.

If you directly steal from a shop, even if you pacify the shopkeeper afterwards, the word goes out and other shopkeepers may then charge you higher markups. (Even if you killed the shopkeeper, but not if you killed them without actually stealing anything - perhaps the Kops are sharing this information around).

Expand the behavior of the ‘unpaid’ object flag so that it tracks items that you have stolen from shops or looted from shops with the shopkeeper absent or had a pet steal. Unpaid items outside their shop can render as “stolen” in the object name, and attempting to sell them inside a shop (even if not the same one it was stolen from) will just cause the shopkeeper to claim it and give you no money.

Gently nerf the ability of pets to steal from shops, so that a player with a stack of meatballs or a magic whistle can’t clear out an entire shop. Suggested ideas:

• Make apport less easily exploitable, requiring more in-depth training than just feeding your pet after it drops items next to you.
• Track the total amount of value lost to a shop by a pet moving items out of it. Once this value exceeds some threshold, the shopkeeper intervenes, either by turning hostile if you continue letting your pet steal after a warning, or attacking the pet.
• Track items that have been stolen from a shop (probably by marking them with the monster ID of the shopkeeper). You can’t resell stolen items; the shopkeeper won’t offer any money for them, instead they will grin and say “Thank you for returning my stolen [item]”, taking ownership of the item. However, this doesn’t solve the problem where you really do want most of the shop’s inventory for yourself.

If possible, work in a “pet-ty theft” YAFM somehow.

New shop type “thief shop”. Contains blindfolds, lockpicks, thiefstones (if implemented), rogue/pickpocket gloves (if implemented), cloaks and daggers. Something special should happen when you directly steal from a thief shop.

Shopkeepers track your petty thefts, and automatically anger if you steal a valuable single item or 50% of their stock or items totaling more than 1000 zorkmids.

Shopkeepers recognize items that they originally owned but were stolen from them by pets, etc. They reclaim ownership of those items if you return to the shop with them, or possibly get angry.

Stealing from shops via your pet doesn’t directly anger the shopkeeper, but the shopkeeper is aware of it and raises their prices to compensate and eventually won’t let you reenter the shop. Alternatively, the shopkeeper simply will block the entrance as long as ‘‘any’’ monster in the shop is carrying unpaid items, but this could be circumvented with a magic whistle.