Not all settings are in ~/.local/share/shotwell
Mandatory: Shotwell version the issue was seen with
0.28.2
The expected behaviour
Deleting the folder ~/.local/share/shotwell should reset the application to a fresh state.
What was actually happening
Additional settings for the app are in org.yorba.shotwell, but the average user isn't going to find them. (It took me forever and I think I'm pretty smart!)
Steps to reproduce the issue
Delete ~/.local/share/shotwell and relaunch shotwell. The scan folder is still set to the previous library.