QSK?
it would appear that traffic information IS NOT recognised by the FAA as being a prime UNICOM function.
MrApproach highlighted the section of the FAA AIM that deals with this.
Specifically
Information Provided by Aeronautical Advisory Stations (UNICOM)
1. UNICOM is a nongovernment air/ground ...
2. On pilot request, UNICOM stations may provide pilots with weather information, wind direction, the recommended runway, or other necessary information. If the UNICOM frequency is designated as the CTAF, it will be identified in appropriate aeronautical publications.