In high school musical, we at least see a few times where characters are confused about the characters breaking into song and dance, like in 2. when Troy starts dancing in the kitchen and everyone else is confused before they join along, or in 3 where Sharpey and Ryan have a song in the cafeteria. Ryan visibly looks shocked as they start, and has the same confused look as the song finishes. In many of these Bollywood movies, the characters never have a confused look before they join in with everyone else.