The problem: Groups of three bots (often with random letters for names, exactly like the gold farmer spammers) stand at the boss spawn in public dungeons and kill the boss as soon as he spawns, making it extremely difficult for normal players to earn the dungeon achievement and receive soul gem drops of their own.
I have started a second character after getting my first one into veteran ranks and every single public dungeon instance I have been in has had bots camping bosses, this is already a major problem and they will spread very soon to the 50+ dungeons and the highest tier of soul gem (if they are not there already - I have seen groups of them grinding on npcs to level in Eastmarch so it will happen in the very near future)
The reason for the problem: Gold farmers have identified soul gems as a high value low risk item which can be farmed easily and repeatedly (disrupting regular players and reducing their ability to get the items for themselves in the process) and which is then converted to ingame gold by selling to other (innocent) players - which I assume they then sell for out of game currency.
The solution to the problem: Remove soul gems from public dungeon boss loot and introduce a series of daily quests, one for each tier of soul gem, which reward something like 5 soul gems for completion.
This will not stop the gold farmers from collecting the gems but it will limit them, and it will restore the public dungeons to their intended purpose and make life a lot less frustrating for your regular customers.