LTC4001 Battery Charger

I have noticed that when the TIMER and /EN pins are grounded and the /CHRG pulled high through a pullup resistor (2K), the /CHRG pin oscillates at 10ms low and 20ms high.when a battery is absent.  Can I depend on this behavior for battery absent detection?  The data sheet does not describe this condition, but it is certainly useful if it is not just an anomaly.