The Z48/Z49/SW02 is a component capable of being rated waterproof.
The term "highly water resistant" is used rather than "waterproof".
SureFire tend to reserve the term "waterproof" for those products it has individually tested to ensure they are watertight.
Operating the push button pressure click switch has no impact on the waterrproofness.
Far more important is the o-ring seal on the TailCap end of the body.
This is especially true when threaded components are rotated and risky when the o-ring seal is exposed [to dust, dirt etc]
This is not correct.
When the click switch is latched on, the TailCap can be rotated (unscrewed) from the body past a point beyond which the light will deactivate.
When the TailCap is rotated beyond a point at which the push button pressure switch no longer activates the light, the flashlight is Locked Out.