When I first got my FZ6, I stopped the engine using the kill switch, then I would turn off the ignition using the key. After walking away from my bike several times leaving the key in the ignition, I changed to stopping the engine with the ignition key and then pull out the key.
Here's my opinion:- the "kill switch" is a supplemental backup to the ignition switch, not a primary method of stopping the engine. Having worked on the bench as an auto mechanic/technician for over 25 years before becoming a Japanese car manufacturer District After Sales Manager, I have seen many, many switches of all types fail from simple, repetitive use. The kill switch (to my mind) is a failure waiting to happen. Leaving it in the "run" position minimizes the possibility of it failing, im(very)h opinion.
As always, it's a personal choice, of course, but I think the advantages of using the ignition key rather than the kill switch as the primary method of switching the engine on and off outweigh the disadvantages.
As a bonus, when I do the usual panicky "what did I do with my key?" personal strip search in the restaurant, I always find it in a pocket.
