I could not resist testing this since on most of my camera imports in FCPX , I had “reel number” information = the camera card name is automatically inserted in the metadata.
The reel number metadata must be active and the import procedure must be done properly from the camera card (no drag & drop ) then you get the same benefit as ingesting from tape in AVID.
Most of the time people are dragging the media directly on the event which does not auto enter the reel number.
In this situation one must group select the pertinent media in the event and type the desired reel number info, it will apply to all the selected clip : simple assistant work…
FRANCOIS