Not a feature that I would use personally, but I could see how/why some others would use a feature like this.
Rather than an “LSP” note on specific cards, I could see this being applied as a filter category under the comprehensive list of the player’s cards.
For baseball players, I would imagine that fields for MLB debut and final season year (or game date) would need to be added to the PID. (Maybe something like “years active” for other sports?)
The filter could then use that data to filter the available cards by year +1 year (to capture the cards released for the players final season subject to the publishing lag).
Once working satisfactorily, there might even be an opportunity for another filter to work similarly but capture only the minor league years.
This would require a lot of data input, might be a way to make this work.