This is one option. Another option would be to clearly separate ineligible monuments with a different color. This is how I tried to do it when I still had an illusion that my effort is needed by somebody.
Looks pretty, though you have only one ineligible monument in this list. I suppose in my case a lot of monuments with a mark "do not upload to commons" will look odd.
So, I did some corrections in commons template. Please look, does it work correctly for Moscow bridgehttp://commons.wikimedia.org/wiki/Category:Moscow_Bridgenow? If sow, I'll prepare the same for other monuments (eligible only, unlike Moscow bridge).
-- Regards, Andrij