I had to send in my Leica II to get sorted out after a business card mishap. User error maybe, but I'm never trying that technique again.
I've started to pre-trim the leaders on a handful of my fresh rolls, maybe 4-6 at a time depending on how much I'm shooting the II. Just pull the film across the width of the baseplate and eyeball the cut. You can make it a fun little ritual, easily done while sipping a beer with Netflix or an album on. That way there's a stash ready when you are, and you can just grab 'n go without fumbling around on the street. Boom -- just as easy as loading an early M.