Final answer:
Pilots operating under VFR within a TRSA are encouraged to contact ATC for traffic advisories and safety benefits, even though participation is voluntary.
Step-by-step explanation:
While participation in Terminal Radar Service Area (TRSA) services is voluntary for pilots, it is recommended that pilots operating under Visual Flight Rules (VFR) are encouraged to contact ATC (Air Traffic Control). This communication with ATC enhances safety by providing traffic advisories, sequencing, and separation within the TRSA. It is important to note that contacting ATC does not constitute control in the regulatory sense but offers important safety benefits to VFR pilots.