Hi,
I live in Japan and just went back to Canada for a bit. I went through Narita and had no problems.
As @han mentioned, they likely don’t have time to read instructions but you can tell them when you pass your chair over.
For example, I showed them the switches for manual/breaks, how to disengage the battery (I did it for them) and where not to touch/lift. And everything was ok.
You never know when something could be broken though, so I always take pictures of my wheelchair as proof that it was not broken when I handed it over. (I had an experience in the past where the airline tried to say “it was already like that”.) It won’t prevent it from getting broken, but at least will help if you need to be reimbursed.
That being said, I’ve flown nearly 100 times in my life and only had it broken 1-2 times.