My PIL comes to stay about 6 times a year - sometime for up to a week. They love TV.
We have 3 Tvs in the house already - one in the living room, one in the playroom and one in mine & DH's room.
MIL has asked to have one in the spare room.
When they're here I let them watch whatever they want to.
I don't really want another TV in the house, and we certainly don't need one. BUt MIL is helping us a lot with the children and I kind of see that she'd like to sit in the room and watch what she wants and I'd hate to be considerd inhospitable.