Yes, it is true you must know your customer because every people in cryptocurrency have a distinct attitude, and sometimes they have a mask that represent that they just want to scam you or steal your money. they are acting like they are a good people but behind of that they have a bad intentions, but there is a some customer that honest and good when it comes to that matters. I also advice this topic to other people involving in cryptocurrency because it is crucial to know because many victims of scam are really regret it, they always say that after it happened "you should know your customer first" for all cryptocurrency user there please keep in mind this topic.