A remote pilot arrives at the flight site and notices they feel unusually fatigued. Under Part 107, what should the pilot do?

Why →Under 14 CFR § 107.17, no person may act as remote PIC when they know or have reason to know of any physical or mental condition that would interfere with safe operation. Fatigue is specifically addressed in the IMSAFE checklist (F = Fatigue). An untrained bystander as VO does not remediate the remote PIC's physical condition.

The trap →A bystander VO does not fix the pilot's impairment, and caffeine masks fatigue without restoring reaction time or decision quality. The answer under § 107.17 is: don't fly.

Field note →Research consistently shows that fatigued pilots underestimate their own impairment. The IMSAFE checklist exists precisely because pilots are poor self-judges of fatigue. If you're asking whether you're too tired, you probably are.