I don't know what JGC did, but you can detect the button's DHCP request and consider it pressed. I didn't want to do something that hacky, so I made my own Dash:

https://www.stavros.io/posts/emergency-food-button/

Come to think of it, I should have added an SMD switch to it, maybe I'll make a new one with a 3d-printable case. That's an idea...