Some signs for businesses can be as subtle as Godzilla — big, gaudy, flashing, even festooned with balloons. The fewer of those, the better.

The restrictions and costs of professional licensing don’t apply only to doctors and lawyers. Hairdressers, decorators and others must deal with them too.

Several businesses from day cares to grocery stores and hair salons closed Monday across the U.S. in a loosely organized day ...