[LearnedfromTV]

Sweating and giving advice to someone in whom you have no financial interest: fine

Sweating and giving advice to someone in whom you have a financial interest, but who is allowed to and chooses to make his own decisions: fine

Sweating and giving advice to someone in whom you have a financial interest, with the understanding that he will do exactly what you say, in a tournament you are also playing: equivalent to multiaccounting and unethical.

Scenario 3, but in a tournament you aren't playing: fine.

Tough to distinguish between 2 and 3 in terms of writing rules, but as an ethical question that's the key distinction.

A secondary issue is the degree of the finanicial interest; a full stakee "following orders" is more concerning than someone who has sold 5%. Of course only full stakees are likely to always follow the ghoster's advice.