Don't know about coached to rip (although some of ours that play League have been), 2but we certainly see a lot of greedy players who go for the ball and try to trip because ball = tries. We try to discourage this and get them to earn the ball (tackle / ruck / maul to gain possession). Either way I've not see a dangerous rip attempt, other than a few flailing elbows, and once coached to maul a rip attempt that's not immediately successful often becomes a maul anyway (which only has a 5 second lifespan at this age) so I wouldn't worry too much about it.