When nearest hits errors like it can't find where it's supposed to print or similar, it returns CUPS_BACKEND_OK (0) but discards the job silently (from the perspective of the user). Trying to print the document again does not give you any hints on where the first job went.
If we instead would return CUPS_BACKEND_CANCEL on these types of errors, CUPS will indicate that the last printer job did not complete.
> # lpstat -t
> printer nearest is idle. enabled since Thu 29 Oct 2015 06:19:16 PM CET
> No near printers for terminal (52:54:00:D7:5C:66) in configuration! DELETING JOB
CUPS_BACKEND_CANCEL is described as "The print file was not successfully transmitted because one or more attributes are not supported or the job was canceled at the printer. The scheduler will respond to this by canceling the job.". It's been present since at least CUPS 1.3 - can't find older documentation on cups.org.
We'd have to reconsider what information is safe to share to users through this channel though.