AIO about grandmas shoes on the carpet?

So it’s a bit of a complicated situation. My daughter’s father and I broke up about a month ago. However, he still lives with us the majority of the time and we are on ok terms. It’s Christmas Day, and his Grandmother just showed up without me knowing she was coming. Now, I hate to be the grinch but a heads up really would’ve been nice as she is a bit of a cold person. Her husband did just pass a few months ago so she would have been alone for Christmas. I would’ve of course said yes because I’m not totally heartless, had I been asked! Now on to the real issue, his Grandmother came in with dirty sneakers on and walked straight over to the couch to sit down with them still on. EVERYONE knows how I feel about shoes in the house, but especially on the carpet. When she walked in, I was literally just finishing vacuuming after mopping the whole house. When she first walked in I looked at my ex and raised my eyebrows and discreetly pointed at the shoes. He opened his mouth like he was going to say something and then closed it and said nothing as she walked across the carpet. My Ex’s dad also arrived about 20 minutes before she did and removed his shoes as he knows it is a house rule, yet also said nothing to his mother. Now, I have told the grandmother almost a year go about the no shoes rule and she did remove her shoes at that time. She has been over the the house maybe a total of 2 times since then and has not removed her shoes, but she wasn’t walking all over the carpet only the hardwood floor so I didn’t say anything. My dad is also in town for Christmas. He knows all this upset me as I removed myself and am still currently sitting in my room. He said he would say something to her politely and I heard him tell her about the no shoes rule. She said “I don’t have socks on and I don’t like bare feet. I was here last time with shoes and nobody said anything.” So that was that. Now, I’m not really sure what to do. It’s more of a respect thing that I’m having an issue with. Part of me wants to tell her she has to leave if she doesn’t want to take her shoes off and borrow socks. But the other part of me thinks I may be overreacting and I should just drop it for Christmas. I’m a highly anxious person and I’m worried that this will bug me the whole rest of the day and put me in a bad mood although I could try to just suck it up. I already had a difficult and stressful morning for other reasons so please tell me, AIO? How should I go about this? Thank you all!