After reading all the replies I think it is one of two things.
1. It is purely random and status has no effect on cabin selected.
2. They look at the Pinnacle's history of onboard spending which is usually $0 and takes advantage of all the OBC they can get (next cruise, stock holders, Ta, etc.) and group bookings to get the best price. Plus they know he will be back irregardless of the cabin provided. That may not be the case with with a second time cruiser.
I know Royal's IT department is not the best in the world but they could easily have an algorithm to maximize onboard spending and encourage those guests likely to spend more on board to return by giving preferential treatment when it comes to cabin selection. In the past before Royalup I saw a lot of first time cruisers get upgraded.
For me I think it is number 2.
BTW The cabin was upgraded with a small Royalup bid by the Pinnacle.