The rule was just announced last spring, when the ASTM standard was finalized. I am shocked that the NCAA would require a piece of equipment that was not even commercially available at the time of their announcement.
Although similar box collars have been in use for years, the exact box collar required by this rule, with both the wing design and this level of force impact rating, has only existed a few months and has not been used in many competitions, let alone this level of competition.
Do I think the collar is safe? Yes, as far as I can tell. We bought one at my HS, installed it right before the district meet, and it was fine. None of the kids freaked out or had any problems.
The concern that many college coaches have is that the collar will impede the movement of the bending pole with the bigger poles.
It's a big ugly mess and I don't like it. All the NCAA had to do was delay implementation for a year or two, give people time to get used to it and prove that the exact collar being mandated is safe. I truly believe that they have set themselves up for a lawsuit if any athletes come up short and get injured this year. Juries don't like student athletes being used as guinea pigs.