a) I have not heard about this before.  Apparently you have not either, if you "stumbled across it".

b) Putting used Paraquat into used drink containers?.....  Isn't that a bad practice regardless of which product you are using?  How is Paraquat any different?

c) Is there a requirement to show proof of training before the product is purchased? If not, how will "The Powers That Be" enforce this training?