If you go to the @bittrex or @poloniex Steemit account, check their wallet transaction history, you will see many many many people posting private memo keys directly on the blockchain, it is a very good thing that you have posted this here. It's a very good warning.
I truly hope people will read this, before they mess up...
exactly why this post is important!
This is a very easy mistake to make.... but a very expensive mistake.
They must have updated the code or something bc it doesn’t show it any more