The cost for parking will of course be limited as otherwise you could simply send the car out to drive around the block until you're ready to leave. That may not provide a restrictive limitation but it will be a limit in some way.
I'm now imagining huge traffic jams caused on purpose to enable electric vehicles to crawl around the city for several hours to avoid paying massive parking costs.
I can easily imagine cities mandating autonomous vehicles having to pay (automatically I guess) some kind of 'congestion' fee after driving a certain number of miles without a passenger or without covering any real distance.
I'm now imagining huge traffic jams caused on purpose to enable electric vehicles to crawl around the city for several hours to avoid paying massive parking costs.