We have this rule for three reasons: Firstly because we don’t want RuneScape to be just a game in which you can buy your way to success, if we let players start doing this it devalues the game for other players. We feel your status in real-life shouldn’t affect your ability to be successful in the game.
Secondly we cannot see the half of the transaction which occurs outside the game, and if players swap items for external benefits we can’t see, to us it looks like an unbalanced suspicious trade.
Thirdly, often when players attempt to break this rule and sell items for real cash the items are actually stolen, so you could even end up getting in trouble for receiving stolen property. If you purchased an account you might find it suddenly returned to the original rightful owner and yourself out of pocket.
We have recently launched a new tracking system which means we can detect this sort of 'real life' trading very easily. We maintain a list of accounts which are known to sell items in breach of this rule, and watch who trades with them. This means if you buy an item off someone we are watching we will know about it.
We would also like to remind players that there are NO official RuneScape gold websites. Even if the site you are thinking about buying/selling RuneScape gold with looks professional, it doesn't mean it's a service we are running, and you will still get banned for using it.
In the last week we banned 992 accounts for real-world trading related offenses, as we have very reliable methods for spotting this sort of thing now.
We've even had queries from players complaining they didn't receive an item they paid real-life money for - which given it's against the rules anyway seems a strange thing to tell us! So PLEASE make sure you read all our rules, which can be found here.