Can't meaningfully disable self-service transfer/cancellation once enabled
To replicate:
- Create an event. Enable self-service transfer/cancellation.
- Register a participant, receive the email to the self-service update page.
- Disable self-service transfer/cancellation.
- Click the self-service link. Note that you can still load the self-service page even though self-service has been disabled.
This is an easy fix, but given the many self-service issues, I think a refactor is in order first, so I'll submit that before proceeding.