Wabi:
Can't help you off the cuff as we don't own one, but Cookie's new Canon R 7 power switch has 3 stops - "off, camera, and video." I can see that one being blindly carried too far when one is not looking and in a hurry. I'd rather it be on/off with a camera/video mode switch elsewhere.
Surfed up a DMC ZS50 pdf owner's manual, and there's a lot buttons clustered in that shutter realm. Tough deal for fat fingered old folks. Might there be an option in the unit's setup to disable video or reassign a different task to that particular button? Cookie can change button functions on her Canons to damned near any other task she might want them to execute.
Edited:
OK. Took a minute and surfed this up. I hate such videos and will not view it, but sounds like button functions can be reassigned
custom function linkTry surfing up "DMC ZS50 assign buttons" Looks like one can do at least two customized settings and find quite a few web pages offering help.
Good luck,