Outdoor shoes inside

AIBU My sister and BiL live 80 miles away but come to me about 3 times a year ,they dislike my husband with good reason and as I don't drive the train journey is now not an option for me ( last time I did it it took 6 hours including 2 buses and changing trains)They see 3 different relatives in the one day.Anyway when they come they are both 70 but as for as fiddles and I am always glad to see them but they refuse to take their shoes off and I have cream carpets.They say" we are not taking our shoes off we will sit in the kitchen" but my kitchen is colder than the rest of the house and we can't all sit round the table.I said " no come in the lounge it's more comfortable/festive" to which there was a lot of h huffing and puffing my sister took her ankle boots off but my B i l point blank refused .What do you think?I asked them what they did when they had just visited Bils very houseproud daughter they said we say in the kitchen...