@docpop It is too complicated to write it off as purely to save money on parking. It could be rebalancing the cars from popular drop off areas to popular pickup areas to minimize delays. The same way you’ll often have many empty buses on return trips during rush hour.
@LogicalApex I totally agree there are secondary benefits to keeping these cars on the roads such as collecting data, moving cars to destinations where there might be pick ups in the future, and arguably even free advertising, but my friends in the industry say that the main purpose of deadheading is to save money.