I wouldn't stress too much. My son is 2.5 and has just recently started to have an attention span long enough to watch a movie. If he watches one, it is usually Monsters Inc, Shrek or Shrek 2. He would probably watch them all day every day if we let him, but of course we don't and at 2.5 he is easy to distract and redirect his attention elsewhere on to other activities. So, basically I can see nothing wrong with letting your four year old watch a kiddie movie every now and then. The way I figure it, watching TV/Movies is only a problem if the kids don't or won't do anything else all day as it can lead to obesity etc, but if they are only watching TV/movies in moderation and getting enough exercise and stimulation in other areas, then there's probably no problem.