The two questions I always have for people selling strategies / bots / etc. is
1. Can you replicate it on a fresh new account. And announce the account before you start. That way we know that you don't play on N accounts, and then simply announce the best result.
2. Why don't you just instead use your own strategy? Why does it make more sense going through all the effort of selling it, when you could simply use it
I know that you know the answers to these questions, I know you are asking it just to tell them how they are basically selling a scam, and I know you know it is impossible to "guarantee" profit.
However I just want to answer via your questions to anyone who may have doubts. Nobody, and I mean NOBODY can guarantee income, they can't just start a new account, let it be known, and then do it live action so that we can see it, even if they get lucky and make it once, they can't do it few times back to back, a guarantee means they can start 10 accounts, let us know before hand, and do it on 10 different accounts and make a profit in all of those 10, even 50%+ of it being profitable would be good to prove me wrong, but they can't, it is impossible, mathematically impossible. And yes they are not doing it to profit themselves BECAUSE it is not a way to profit, selling it guarantees profit, using it does not.