Originally Posted by CosmicGirl

As an update: this past week was the first time the Fastlane thing semi-worked for me on the app. I received a notification 30 minutes before the pick-up time and was offered one car which - if accepted - would have the keys in the vehicle by the time of my arrival, which is not typically the case in this location. I checked the app to see my options but ended up not accepting the car that was offered and opted to go to the desk instead. Initially they offered me the same model with different plates but I managed to get a single category upgrade with platinum status at the desk.

If it matters at all: I had two different post-paid bookings which partially overlapped, and I modified the pick-up time for one of them a few days before. I was only intending to keep one of the bookings but wanted to lock in the price so I booked the two days that would suit me to keep my options open. The only booking for which I received a Fastlane e-mail the day before was the one which was modified. They never sent anything regarding OLCI or Fastlane for the booking which wasn't modified (and I ended up cancelling anyway).