I often put nursery rhymes on the TV via YouTube, you often get the adverts, but these can be skipped.
Sometimes YouTube provides an "ad" which can be very long (15 minutes or longer), and often inappropriate for my 6 month old daughter, however I just got the most inappropriate ad possible for a child.
I left my daughter watching nursery rhymes whilst I did some washing, suddenly I heard the term "suicidal thoughts", I went from the kitchen to the living room, there was a 15 minute ad discussing "suicidal thoughts in society"
I've now uninstalled the YouTube app from the TV as a result.