Who cares if a late night comedian's voice-over says Period and displays an exclamation point? How influential is that? It is thoroughly illiterate, and wrong... or is it, if a powerful governor bases their remarks on the misinformation?

https://www.grammarly.com/blog/period/

A period is either a full stop, or a certain uncomfortable time of the month for a Woman... for a cis woman, some might disclaim.

“They have the right not be harassed, not to be denied, not to be arrested for peaceful protesting. Full stop. Period," said Newsom.

"We have the best three year record of any modern American presidency. Period. Full stop.”

"Period, full stop" is a fine example of tautology. Tautology is consider poor style and a red flag of ignorance. It is like saying "ATM machine". That is, Automated Teller Machine machine. Or, "widow woman", cited by the site.

On the other hand, and still not considered good style, it might be explained as saying the same word in American English and also in British English, like "hood/bonnet", "trunk/boot", "windshield/windscreen", "chin/pecker" and "fender/wing".

All the best,

Rowena Cherry