These people need to take a class in common sense...

Completing 1 quest with 5 characters = 5x the monetary reward.

If I was a gold seller, yes that's 5x more profit.

But if you are simply playing the game normally with 5 Characters at once, you'll have 5x the expenditure too... equalling a grand total of 0 (thats ZERO, NONE, NIL) monetary advantage over a single-player. The only difference it makes to them is they can't ambush you alone while questing so easily, and how is that any different from questing with a friend?

But of course I don't have to tell you guys that do I? *cough*

/rant