Depending on whether this is supported, the text of /bookings/{id}/events - CANCEL should read "Cancels a PENDING or CONFIRMED booking".

The current spec does not seem to be explicit about this so I guess implementers are free to implement this behavior without really violating the spec. But it would be good to make this explicit. We would like to be able to explicitly cancel PENDING bookings with long expiry times so that we can early release assets (and make the available to other users) that result from long winded interrupted booking flows.

Implementers could still be free to explicitly not support this behavior, but then this has to be reflected somehow in the cancel response (PENDING_BOOKINGS_NOT_CANCELLABLE or something). I don't think I would go as far as to have this behavior specified in a process identifier.

The quick solution would be to just update the text in the spec to read "Cancels a PENDING or CONFIRMED booking".