I do want to know if my idea or decision on this is the right way?
you've told him it could make all their money disappear. the first withdrawal may work to convince them to deposit a larger amount. if that has happened, then they may not be able to make any withdrawals.
what you did was correct by providing an explanation regarding the risks of this unauthorized method. if they don't heed your advice, then forget them. there will be no benefit for you if you put too much pressure on those who don't believe in you.
We all know why these ponzi schemes run successfully because our greed overpoweres our mind and ability to think that we choose these short paths to be successful but when we realize about it it's too late so we should avoid engaging in these and be satisfied in small amounts only.
A scheme like that isn't the same as cloud mining which we usually find as advertisements on social media. for some people who already understand how such scammers cheat, it will not be easy for us to deposit money for small profits. but those beginners who have high curiosity will be very interested in short profits even when they don't do anything.