KevinR wrote:
> I like your suggestion...

Well then, I'll re-post my sign suggestion here:

STOP!

Read this!

If you are a Mt. Whitney day-hiker, then
YOU ARE LOST!

This trail does NOT go to Mt. Whitney.
It does NOT go to the Whitney Portal road.
This trail goes deep into the backcountry.

Turn around and go back to the junction
behind you!

Unfortunately, Seki people don't seem very enthusiastic about public suggestions. (You should have heard the response I got with my idea of placing a remote-reporting weather station at the summit hut. ...but I'll save that for another thread.)