Apparently, by default, all cells in a worksheet are locked (Format Cells
Protection). Consequently, when I set worksheet protection (Tools
Protection Protect Sheet Password), all cells are protected.

I want to protect just 4 cells. So I think I want the default for all cells
to be unlocked. Then I would lock the 4 cells and set worksheet protection.

Of course, I could manually select every cell in the worksheet (A1:IV65536)
and change the Protection format to unlock. But besides being a "pain", it
appears to increase the worksheet size "unnecessarily".

Is there a better way to change the default cell protection to unlocked?