I expect MacBeth to be one of the most produced plays in the English speaking theatre world, so it makes sense that many noteworthy accidents / incidents happened. However, Hamlet has apparently been staged even more often, and it would be interesting to compare the number of incidents, but since there's no curse for Hamlet, no list of incidents exists, at least not on Wikipedia. Macbeth's curse could also be a self-fulfilling propehcy in some cases.
It also has a number of fight scenes, which are dangerous, and is often darkly lit. I don't know if you could really control for all of the variables, but the thing about the name is just a fun joke among theater people. Few actually believe it.
I will note that the worst injury in my troupe's 20+ year history was during a production: a one in a million bounce by a blunted stage weapon. It is the only time anyone got taken to the hospital. But there have been other injuries, and the last time I directed that play I made sure the injury count was zero.
(Credit to my fight choreographer, who made sure of it.)
