Buying/Selling Auth Codes

I think that buying/selling auth codes should be allowed. If I am correct, the reason this is prohibited is because of buying/selling auth codes are easy scams.

I recently did a trade with someone (not on sythe). I sold him an auth code from rsbotting.com. The trade was quite simple, but also kind of long. What I did was I went to the rsbotting.com and went to the bot my trader wanted. Instead of suing paypal to buy it (this is because using my paypal will send auth code to me instead of my trader), I used mail-in. I put my trader's email address for who is receiving auth code. HE paid me after he received the auth code.

THis way prevents scam and I think this should be allowed.