Roger (K8RI) writes:

I seriously doubt they can. I can discern the flicker in *some*
fluorescent lights, but I can not discern 120 cps on a strobe. I
think what they are seeing is the "sputter" of a cold lamp or a light
that isn't starting correctly. The flicker I see in those lamps is
considerably slower than 120 or even 60 cps.

Peripheral vision is much more sensitive to flicker than central vision. Some
people will perceive an irritating flicker in a lamp or computer monitor each
time they turn away from it, and yet the flicker will disappear when they look
directly at it.

The perception is limited to the impression that the light is flickering; that
doesn't mean that they can count the individual flashes.

First, for any flicker the phosphor has to be defective ...

How can the phosphor be defective?