I am the same way in that the tv is available to the early arrivals and late leavers as a perk for the extra hours they are in care compared to their friends. It is a great diversion because time passes without them realizing everyone else left 45 minutes ago. It also prevents them from getting everything out in the playroom and making a mess before the others have even arrived - mostly because the first child won't pick up and that isn't fair to the others. The fact the tv is not in the playroom should be a good sign to you that it is a special part of the day and not a constant activity.

Why not just ask your provider about her use of tv - which should have been done in the interview. Also figure out why it bothers you so much. Do you still get crafts home or your child able to sing a song or count to ten then you know that other activities are going on and rather than ban anything from your child's day you need to look at the balance of activities.