[renewiltord]

All the comments in response are clear then that it is a question of degree. At x deaths caused, we stop permitting this. That means the discussion is only moved to determining what that threshold x is. And so the right thing is to move past that to find what the cost-benefit analysis is.

[ModernMech]

X is the number of people who would overwhelm your local hospital system. If the cost of you getting a haircut is that it renders healthcare inaccessible for your region, such that they cannot care for people who need it (e.g. people who get in car accidents) then that cost is too high.