Not even remotely true.
Jaffas run extra optional training on Monday's on top of the existing team training sessions.
I cannot get my son to the Monday sessions this year and was asked why I couldn't get him there. I gave the reasons behind it and was open about Jr doing regular sessions outside of the club to subsidise his training and the club are happy where it stands.
My son is one of several in his age group that get training elsewhere. Although I can't speak for the rest of them, my son and I have had no negative feedback or encouragement to stop the external sessions.