What? Players get injured in home plate collisions all the time, sometimes seriously. It's the single most dangerous play in the sport. When one guy is squatting down and another man running at full speed plants his shoulder in the other guy's head, it's not "a freak injury" when someone gets hurt.
There are only two ways that scenario should occur.
-1) The catcher is using incorrect form
-2) The runner goes well out of the baseline to initiate contact
If the catcher does not have the ball, he should not be blocking the plate. Correct form dictates that the catcher stand a foot or so in front of the plate (giving the runner the entire plate) until he begins to catch the ball. At that point, the catcher's left leg steps in front of home plate, on the third base side (with toes pointed at the runner, as to avoid knee/ankle injuries) to take away the plate.
If the runner slides, the catcher drives his right knee into the ground towards the runner to lower his center of gravity and enable him to make a two-handed tag on the sliding runner, and swivel through, coming up ready to make a throw to another bag.
If the runner does not slide, and attempts to run over the catcher, the preferred solution is to sidestep at the last second while applying a two-handed tag (the runner is essentially applying it to himself, by running into it), spinning towards the diamond to avoid collision and be ready for another play. If a collision is unavoidable, the goal is to roll with the blow to dissipate some of the force. Masks should be kept on for plays at the plate, helping to protect the head and face from direct blows and general concussive impact. The catcher should be in an athletic position, but not in a squat, as this opens his head up to direct impact. The blow should be taken first in the hands/arms, acting as shock absorbers, and then in the shoulders, chest, and midsection. As the impact begins, the catcher should begin a diagonal falling/rolling action (again, rolling with the impact rather than bracing against it) to allow the charging runner to go 'through' and past him.
This is not easy to do on bang bang plays, but if practiced enough, it becomes instinct. In over a decade of catching at a competitive level (many of those years catching 80+ games per year), the only play at the plate in which I was hurt (but not seriously injured) was my very first, in my first year of catching full-time, when I was blindsided AND used incorrect form. I took a shoulder to the face (I had taken off my mask/helmet) from a bigger, older opponent; busting up my nose and mouth pretty badly (but I held on to the ball! lol). After that play, I learned the right way to do it, and I practiced it enough that it became instinct. As a catcher, you are at as much risk as you put yourself in. If you do it right, you will likely come out unscathed; if you use s**t form, you WILL get hurt.
I've watched over 140 athletics games, and many games of other teams. This play does not happen often at all. I've seen more torn ACL's from sliding than catchers taking a hit. Smart ones, step to the side and tag. Only idiots even block the plate period. If you block the plate, you should pay for it. I bet the rampant drug abuse in sports causes more suicides than concussions. These baseball players pump so much crap in their system like amphetamines and steroids. I've had 3 concussions, and I am fine! I have down periods sometimes, but dont we all?
The bolded selection is very true. Considering how many pitches are thrown in a game, close plays at the plate resulting in a collision are quite rare. It is also true that in a bang-bang play at the plate, a runner is more likely to get injured sliding into the catcher than by running into him. As I stated in my wall of text above, ideally the catcher is able to step aside and/or roll with the tag. Blocking the plate is not smart, and is doubly stupid if done with poor form.
Banning plate collisions isn't just about concussions. Buster Posey broke his leg. Ray Fosse's shoulder was torn up. It's just an excessively dangerous play that doesn't really fit in with the rest of the sport. Maybe back in the days of Ty Cobb, when runners routinely plowed over fielders at every base, but not anymore.
Buster Posey's leg was mangled because he was lazy and used incorrect form. Pete Rose bowled through Ray Fosse because Ray did not leave him enough of a lane through the plate. Unless you have - or are in the process or securing - the ball, get out of the runner's way, and do not come remotely close to blocking the plate. If he were out front 12-18 inches, Rose would not have had reason to initiate contact.
2 out of how many? You guys know you don't have to block the plate. If I'm rounding third in the MLB and the catcher is blocking the plate, I'm going to run him over hoping he gets up slowly. What can the runner do if he can't run the bastard over? Not score?
It's as simple as the bolded selection. If you block the plate, you will get trucked. If you don't, you won't. If you use incorrect form, you will get hurt.
TL;DR - Don't block the plate and you won't get trucked. Use correct form or you will get hurt. No need to add rules because some are lazy and stupid.