Lycan

Why though? 
I mean, I understand in a small sense but shouldn't that kinda be the opposite purpose of having shops in actual safe areas and those that aren't? 
I figured that was the risk that the player was taking putting their shop outside of a safe zone.

Considering the recent rise in PKing and the manner in which Zelrius and Ssendom were killed, players with shops should not be put as risk since it is assumed they are always present in said shops. Shops are also threads that are never closed or awarded col and SP. They are an independent mechanic from normal RP in the floors and as such, do not permit open combat within them. Since it is also assumed that shop owners have crafting equips on at the time they are present in the shops, they are unarmed and unprotected. While it logically is possible, it doesn't have an enforceable mechanic at this time that is both fair to PKers and Non-PKers.

Yea, mechanically on SAO-RPG, shops and the RP of buying an item, is the extent. You're not even supposed to have extended RPs in shop threads. Though i suppose if you created a thread on the relevant floor forum and set it in a shop, then yes, you could have a PvP fight there. But that forum itself is not for extended RP