Vendor npcs giving experience
 

Did merchants give experience if killed? If so, when they did they stop?

Somewhere along the line they were not allowed to have loottables. This part is fixed by Rogean, to allow a few quests to work properly.

EXP though.. I cannot remember.

Merchants, when I killed them on live, pre-velious, did not give experience. I am on unsure if they gave experience on launch or when that changed. Unsure about faction hits.

I'm pretty confident killing merchants did not grant experience. Kunark+, anyways.

Overall no most didn't, and I don't even think they dropped coin/loot either. I would have been camping many of them if they were worth xp/loot (it didn't help that some underconned and hit for hundreds).

They originally gave exp then it got changed. Was pretty early on.

I remember this also. Haven't found a reference yet though.

I don't remember them ever giving xp even pre kunark

I skimmed through the first year and a half of patch notes. Didn't see anything about merchant exp.

Not all merchant NPC's are ubiquitous, and some hold unique commodities. The incentive to slay such fortuitously and in peril might prove abrasive to the overall supply and demand for adventurers' keepsakes and provisions.