Dangerous isn't a readily quantifiable value. Yes, there has been a few cases where disc braked wheels have been ejected. No one is questioning the mechanics of it any more.
And sure, a through axle or a Cotic fork with forward facing brake caliper will remove the risk.
But I guess it's in the vicinity of the risk of being struck by lightning.
Personally I make sure to use steel, internal cam q/r, That's enough risk management for me, and I'm not much of a daredevil.