ATC communications are recorded for later examination by accident investigators or regulatory agencies. Are CTAF frequencies at untowered fields usually recorded? How about manned UNICOM frequencies?
From the AIM:
4−1−4. Recording and Monitoring
a. Calls to air traffic control (ATC) facilities (ARTCCs, Towers, FSSs, Central Flow, and Operations Centers) over radio and ATC operational telephone lines (lines used for operational purposes such as controller instructions, briefings, opening and closing flight plans, issuance of IFR clearances and amendments, counter hijacking activities, etc.) may be monitored and recorded for operational uses such as accident investigations, accident prevention, search and rescue purposes, specialist training and evaluation, and technical evaluation and repair of control and communications systems.
b. Where the public access telephone is recorded, a beeper tone is not required. In place of the “beep” tone the FCC has substituted a mandatory requirement that persons to be recorded be given notice they are to be recorded and give consent. Notice is given by this entry, consent to record is assumed by the individual placing a call to the operational facility.
The use of "may be" for the manned stations would hint at a "no" for the CTAF, UNICOM, etc. (Applies to official recording, liveatc not included.)