Why is unnecessarily pressing and releasing the brake pedal (treadle valve) a risky habit in a vehicle with air brakes?

AAMVA CDL Manual, Section 5.1.7 (The Brake Pedal), p. 5-2; 49 CFR 383.111(b)(4) (implications of low air pressure readings)

This explains a real-world habit to avoid, especially in stop-and-go traffic or while holding a vehicle on a hill, where excessive pedal pumping can draw tank pressure down faster than the compressor can keep up, eventually triggering a low-air emergency.