@woody & others:
sys entry for indicator LED turn it off for good - i.e. it doesn't re-appear during focusing etc. It is even not possible to turn it *on* again, via "h" in CSSU's camera-ui. Of course, changing sys entry works immediately, no reboot is needed.

Huge thanks for vi_ for finding it - I wasn't able to locate indicator led entry for a life of mine.

/Estel