I received an email a couple of months ago stating that the Sonic's tailcap could come off in your pocket; apparently this has fixed that.
Here's the text I added to my Sonic web page:
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UPDATE: 04-13-04
I received this rather disturbing report from a Sonic user this morning:
I have a Sonic (actually I have 3) I like the light very much. But (here's the but) every now and then I find when I take my keys out of my pocket, the end cap is the only thing attached. Is there any retrofit or any suggestions to keep this from happening? I check it a lot but it still seems to happen.
And here's the reply he received from the Gerber/CMG representative:
Thank you for contacting Gerber Blades regarding the Sonic. There really isn't anything that can be done. There should be an o-ring on the barrel of the handle at the base of the threads and that will help secure the end cap. Make sure when you turn the light off that you do not turn the end cap past the o-ring. If you have any other questions, please don't hesitate to email.
This does not appear to be a widespread problem, as this is the first instance that I've heard of.
UPDATE: 04-30-04
I received another email from the same Sonic user this evening, which states:
The Gerber rep suggested Teflon tape on the threads and that has worked great, its much harder to rotate the cap (varies with how much tape you want to use).