Fenix L2D(LD20) tail caps used as twistie?

I noticed that the tailcap switch on the Fenix L2D and LD20 flashlights can be used as a twistie operation for turning on and off the light.
If the switch is clicked to the on position then slightly loosened the tail cap the light will turn off and when tightening the switch the light comes back on. You can even change the modes by loosening and tightening the tail cap.

My question is: Is there any negative effects that can result from using this flashlight as a twistie for a UI?

Will this cause a "parasitic drain" to occur by using it as a twistie when the light is off? (switch clicked on, tailcap slightly loosened).

Thank you for any replies.

No Parasitic current drain. It's fine as long as the threads survive. Keep them well lubed and there won't be any problem.

As long as the anodizing of the threads don't wear out, using the light as a twistie should have no adverse effects.