Legalnoticetext display periodically question

I have a really strange request from my CEO. After I took the recommendation to have the legalnotice pop up on logon, to our CFO he of course had to run it by my CEO.

This is what the CEO said.. "I think that every day is to much, is there any way that we can make this display once a month?"

Now, I have searched, and googled, and techneted every possible thing I could think of.

Does any one know, a way, to have this set to some calendar function? Or on a specific day of the month? I have been unable to find anything in GPO.

Aside from MANUALLY telling GPO to remove it, on the 3rd of the month, then put it back on around the last of the month. I am lost.