What's is a prepared piano?
Please hurr

a piano with objects placed on or between the strings, or some strings retuned, to produce an unusual tonal effect.

Explanation:

A prepared piano is a piano whose sound has changed by placing objects on or between the strings.

personally, i think the games do because it's actually them controlling it. this might cause them to think it's okay to do it for real. as for animated movies i think they are mostly fine because they're animated. also, animation has come a long way causing animated movies to become more real but 30 years ago this wouldn't be as big of a problem as today.