Sorry, but I don't see how anything he chooses to do in his own solo game can be denigrated as an exploit. Now if he's in multiplayer, it's different. But really, snarling at people for whatever they choose to do on their own private machine, solo-player, is just being snarky for no reason.
[Oh, and wolf.... There's a mod available which gives each vendor either 2k or 10k gold. Infinitely easier than mutzing about....]
An exploit is defined as taking advantage of something unintended within the game mechanics. It doesn't matter if its a solo game or multiplayer game. You delusion that somehow MMOs defined what the word means is silly. Yes, this doesn't effect you or I if someone decides to do it, but to argue that it isn't an exploit, then by that definition, there is no such thing as cheating in single player games.
It is not standard game play, thus it is either a cheat or an exploit. Simple as that.