In my 15 years of editing, I have rarely used (if ever) the clip opacity. I would love to be able to hide the opacity handle so that my clumsy hands don't accidentally grab it when I'm trying to move a clip. I can't seem to find a setting for that or a forum post about it. Does anyone know if this feature exists and how to access it?
I've never come across such a feature so it appears you cannot turn the handles off. I also rarely use it. Actually I did this afternoon so it does have occasional use. Like you I sometimes grab it accidentally when moving a clip so I try to always grab a clip by its lower area.
I also find them annoying sometimes, but I also find them very useful occasionally, such as if a piece of music is louder than other pieces of music it is easier to use the handles to change the volume rather than adjusting the envelope. I've also used them sometimes to fade a video clip on one track so that a second clip on another track is emphasised.