I got ahead of myself with indignation on that one, and didn't take into account words that clearly have nothing to do with the author's intended message when they wrote the card in question. I've got a lot of spelling and grammar related rage. I submit the following sentence from the mentioned card: "Wearing a face mask posses a mental and/or physical risk to me." Clearly the usage of "posses" is as a verb, and not the plural noun regarding a group of people as defined in either of the dictionary links. Also it is clearly not intended to be the archaic meaning or the British English meaning from the Wiktionary link. You make a solid argument that the word exists, but you don't address the usage of it and how it's clearly wrong. Are these cards official? I doubt it. Are these cards valid? Maybe, I'm not a lawyer. Are the people carrying them around lazy and or stupid? As a person who reads and appreciates words, and the fact that particular words mean particular things, I say yes. We can agree to disagree if you want.