gear, permits, etc. I suspect they somehow bypassed the ranger (maybe left after hours) or likely didnt have a permit and therefore the ranger wasn’t expecting them.
At this water level there are basically no places to camp once in the canyon. Last time I did this (maybe 5 years ago) it was at 6000cfs and still it was tough to find camp spots.
Honestly, they avoided a potential disaster. Failure on many levels here.