You have the pushbutton switch on the cord, right? I was told by somebody that they just use one of those big, black spring paper-clips over the top. They open it up, put it over the end holding the button down and let it grip the handle. If a safety person comes over, they just pop the clip off.
Your tech was probably instructed to do it by the HFO management which probably came down from Haas. In our litigious world, I don't know why it's taken THIS long to get where we are.
Sombody may also PM you the fix. I can't remember which but, you have to switch a parameter or two as well as use the Door Hold Override setting to get it back the way it was.
Edit: am I going to hell for posting that?