When you buy them Of forums like this... Wouldn't they get an instant ban? I purchased a few auths back when they were allowed on HF. They atleasr, for the time I used them, weren't "instantly" banned...?
There are so many auths in circulation that they can't monitor every single one. It's like botting, there are so many bots that jagex can't keep track. That's why some get banned and some do not.