I worked on one of these. We had giant problems with caching. You have an assumption that the likeliness of the vehicle becoming unavailable but there are so m

I worked on one of these. We had giant problems with caching. You have an assumption that the likeliness of the vehicle becoming unavailable but there are so many ways this isn't true. The edge cases of car sharing can be downright weird. (For example, some services have both app and mobile, and can cancel via a call to customer service. Let's say that a user books on mobile and cancels by app or even by calling to customer service. They are refunded the money. What happens when they then try to unlock the car? What happens if the signal to the car is poor?) The tension between good UX and bad actors is amplified by $20,000 dollar assets and had some of the most difficult problems I've worked in from a requirements standpoint. The easiest thing was to avoid caching where possible.