cops and robbers and minting your own money

Ro is suddenly really into playing cops vs. bank robbers. I find this amazingly old fashioned and I'm not sure where it came from. The especially crazy thing is the hours and hours he has spent drawing his own currency and cutting out coins. His many different dollar bills feature the likes of Ruff Ruffman, Buzz Lightyear, and the Cat in the Hat. He's so intense about creating all the appropriate props for the story. We've been acting out lots of bank robbery without any shooting or guns. It's all about being sneaky and having a good chase before being carted off to jail.