> Historically perhaps. Nowadays the hand has no body behind it, and it has
> a legend that says 'IBM' on the side, or something like that.

Whichever..

> Not really. In a modern country-wide coordinated network operating within
> its normal specs all you get is phase slip, else the whole shebang goes to
> hell very quickly.

A few degrees at 60 hz is quite a lot of variability at 10 MHz.
Point being, you wouldn't want to lock your color subcarrier to it.

Many areas aren't (or can't) be tied to national grids, but have the
long term compensations in place. In Hawaii, we had (until '87 or so) a
steel mill that would load our system enough to visibly slow clocks. My
father in law ran the furnace there, and I've seen the slowdown myself,
both by eye and by scope.

Still, they were dead on in the long term.