If the official observers (OO) hear something that, in their judgment, is in violation of Federal Communications Commission (FCC) regulations, they will send a postcard to the amateur radio station describing the infraction.
Once the test is forwarded back to ARRL field services (and passes), the amateur receives their official observer appointment.
The OO performs his/her function by listening for such things as frequency instability, harmonics, hum, key clicks, broad signals, distorted audio, over deviation, out-of-band operation, etc.
In hard-core rules violations cases, OOs refer problems to higher echelons of the amateur auxiliary and may be requested to gather evidence for possible FCC enforcement actions.
A key liaison in the auxiliary, the OOC assists OOs in evidence gathering and conveys evidentiary materials to headquarters for handling with the FCC.