I think it probably happens quite a bit especially when the senior player feels a youth team guy is trying to stick one on you for his own profile, guess the way this worked 20 years ago was you'd wait until that player got the ball and then show him what a real tackle feels like and probably end his career. Reserve football used to be tough as every team had a few senior guys who were basically in their to look after you.
Don't think bans can be applied to first team games but I wouldn't have thought Klopp would be to impressed with that behaviour.