Well, I hope that you have already made up your mind. I don't feel that the morals or opinions of others should influence your decision. You already know what you want to do.

A bank ATM spits out an extra $150 when you only wanted $100. What would you do?

I know that the ATM scenerio is a bit of a stretch...
I used to play World of Warcraft a good bit. I knew plenty of people that would stand around and wait for Gold farmers to sell their really good gear to people of the same faction. When they did this, they would wait until the person opened up a trade window with the item that they were about to receive came up and then they would reduce the amount of gold that they were giving them...hopefully with the other person not noticing.

The type of gameplay that these gold farmers used, ruin the game for some people. The farmers would purposly try to get the other people killed in the game in order to aquire more targets in the area to raise their level of production. The games economy would also rise to levels that were out of control. These farmers would sell items for crazy amounts of gold because they knew how easy it was for people to buy gold online (which ... btw buy gold from these same exact gold farmers. This drives a lot of people away from actually playing the game and the level of interest in playing the game. These people are making real money from people trying to play a game anyway you look at it.

Your situation is a little ironic towards them. And if you are worried about the actual game company finding out.....Well, you NEVER bought the currency....it was given to you. They can backtrack and never find a transaction of real money from your account.

In all honesty thuogh, I would delete your character and play outside in the sun