Pulling the Ryker "key" off while idling will not shut down the Ryker - you are correct. You mention you haven't left it idling while you went inside somewhere - the Ryker actually does have a 3 minute idle shutdown which I find interesting. If left idling with no ride input for 3 minutes it shuts itself off. It does beep/give warning before doing so to allow for user input.
Oh yeah. I forgot about the 3 minute thing. I've never had that happen.