Concussions are a major worry for every athlete. From gymnasts to cheerleaders and baseball players to football and rugby. Instead of limiting tackling to once a week, what football should work on, is teaching and enforcing propper tackling technique. Yes I know every parent cares about the safety of their children, and I know that coaches care just as much. There is not a coach out there that wants one of their players to get hurt. But practicing something less will not make it better. The saying, "Practice makes perfect" has a legit reason, because the more your do it, the better you'll be. We already sissify our kids by teaching them there are no winners or losers, we don't keep score, nobody gets out in a game and really to not take challenges and learn it's ok to fall and get hurt/dirty as long as you can get back up and learn something from it.
There are a countless different things football can do that rugby already ready does that make help for better and safer play. The first is don't jump into tackling. Why do pee wee football leagues have three year old in full gear tackling?
Practice tackling with out all the pads! When you know you can get hurt too you tackle a lot cleaner and safer which also reduce the injuries of the person being tackled.
Re-enforce proper technique and reward it. Kids love to tackle one another. In the snow, in the mud, in the pool, but don't just yell at them, break it down do they learn it right and if they continue to do it wrong don't ignore address the problem.
No tackling, leads to not know propper safety. You need to create drill and alternatives that reinforce safety.
Also putting this legislation is not going to help the gymnast who falls off the high beam, rings or bars. Would we tell them only practice a handstand or flip flop once a week?
Oh cheerleaders who have girls dropped on their heads as a base, or as a flier fall and hit their head, don't practice that stunt so much. Just hope that you learner in your sleep how to fly and that your bases learn to catch you.