The short answer
Yes, it is against the rules, and yes, accounts get banned for it. Jagex's terms of service prohibit real-world trading — exchanging in-game items or currency for real money — and enforcement against it is a standing part of how the game is run, not an occasional campaign.
We sell escrow protection for these trades, so it would be convenient for us to be vaguer than that. But a buyer who is surprised by a ban is a buyer we have failed, and anyone telling you the risk is zero is either uninformed or selling you something on a false premise.
What the rule actually covers
The prohibition is on the exchange itself, not on any particular method of arranging it. Buying gold, selling gold, buying an account, paying someone to play your account — all of it falls under the same broad heading, which is why every category on this site carries the same warning rather than only the gold pages.
It also means the protections a marketplace can offer are bounded in a specific way. Escrow governs whether money changes hands fairly between two people. It has no bearing on how Jagex views the trade, because Jagex is not party to it.
What tends to get accounts caught
Jagex has never published its detection criteria, and anyone claiming precise knowledge of it is guessing. What can be said from observation is directional rather than precise: the trades that attract attention tend to be the ones that look unlike ordinary player behaviour.
A brand-new account receiving a very large transfer is a different pattern to an established account receiving something proportionate to how it already plays. Repeated transfers from many different characters look different again. None of this is a formula, and treating it as one is a mistake — it is simply the observation that unusual patterns are easier to notice than ordinary ones.
The other thing worth saying plainly: chargebacks and stolen-payment gold are a common route to trouble, because they attract scrutiny to everyone downstream of them. That is one of the arguments for buying through escrow with a verified seller rather than from a stranger with a cheap price and no history.
How to decide
The useful question is not "will I be banned" — nobody can answer that for you — but "what happens to me if I am". An account you have played for a decade, with a bank you could not rebuild, is a different proposition to a fresh account you would shrug at losing.
If the honest answer is that losing the account would genuinely hurt, that is a real argument against, and it is worth weighing before the price. Nothing about escrow, verification or a good seller changes that calculation, because none of them are the thing at risk.
The short version
The payment risk is solvable — escrow and a verified seller handle it. The account risk is not, by anyone. Decide by asking what losing the account would actually cost you.