Why do you recommend an external reset on BT900 nReset pin?

Inside the BT900 module, pin16 (nReset) has an internal pull-up resistor (value 33K).The reason we recommended an external ?stronger? pull-up resistor is just in case of an  ESD issue or something else that pulls down the nReset pin. But in essence BT900 is out of reset (even if no external pull-up resistor is fitted).