I have had this a few times. My child has a friend to play after school or in hols. There are lots of toys and other activities to do. Within 10 mins, visiting g child asks for TV on.
We don't have TV on in background. My child has 20 mins of TV after dinner. They tend to sit on the sofa and just watch TV for that slot of time, not play at the same time.
I have told visiting child that is how we do it in our house and they can have some after dinner.
Sometimes children have continued to ask over and over again, despite there being lots of other things to do.
Have also had it if child has come over with parents. Child has asked their parent if they can have TV. Parent has relayed request to me. I have explained how we do it in our house and they can have TV after dinner. Sometimes parent has just accepted it, other times, they have asked on behalf of their child again, or emphasised that in Their house, they always have the TV on.
I don't want to be rude to guests or totally inflexible, so do you think IABU?