Every now and then we see some horrible pictures of people seriously injured after a sudden startup of motors during setup. Yeah, we all know that we should remove the props while setting up, but letś be honest: after the 10th time on the same night we get fed up and confident. That is when sh#t happens. Been there, done that...
I have seen some alternatives to removing the props, but this one is my favorite because it is quite simple and convenient: use a low amp 12v source instead of the battery. I am using a 1.5A 12v source that is enough to power the controler, but if any motor tries to start the voltage will drop and the controller resets. Even if it doesnt, 1.5A isnt enough to spin a prop to a point of hurting anyone.
It is simple because all you need is an adaptor (or solder your plug directly as I did). It is convenient because you problably have many low amp 12v lying around, and I actually prefer not to use my batteries so they stay fully charged to fly.
Do yourself a favor and just build one. :-)