One of the classic problems around requiring regulations is that people just don’t have, and cannot easily obtain, that much information about businesses sometimes, which is required for markets to actually work.
(Even when information is free or nearly-free, the Market pays people to sabotage it, just like it pays people to sabotage Market competition through buying politicians.)
This is part of my interest in substituting mandatory insurance schemes for explicit regulations, provided the insurance regulations are themselves well-designed. The customer may not know much about the safety of the business, but the insurance company, which has a long-standing relationship with the business, does.
And the less the insurance company knows about the business, the more money it charges for insurance, offsetting some of the risk of harm and potentially communicating risk information to customers.
What we actually wanted to mitigate was risk/externalities, not the number of hair clippers, which is only a proxy.