Since they need internet connectivity to phone home status to McCloud, I don't know why they wouldn't just run an NTP client to keep their time synchronized and accurate?
Moreover the $750 you reference must be a commercial product since you can do GPS on a Raspberry Pi for < $50 easily? Which product are you thinking works for this scenario? Think I've seen everything from $300 to $13000 solutions for this over the years.
I doubt these machines are internet-connected. Most likely is that the store manager notices the machine has gone into its cleaning cycle and manually marks the item on the menu as unavailable.
Moreover the $750 you reference must be a commercial product since you can do GPS on a Raspberry Pi for < $50 easily? Which product are you thinking works for this scenario? Think I've seen everything from $300 to $13000 solutions for this over the years.