For years, the NFL covered up data of the longterm damage of concussions. For that, they should be held liable. But today, the dangers of concussions are known. It's one thing to play not knowing the risks. Now that it's known, a lot of the burden falls on the players to decide whether or not it's worth the risk to play. Having said that, the NFL would be idiots to not try to protect their players as much as they can. I think they are making strides with the on-field testing from an independent doctor, tests which clear them, etc. Helmet technology will continue to advance but, bottom line, nothing is going to remove the risk 100%. At some point, players have to take on the burden of responsibility.