I have the same Flier 400A esc. I used to have a lanyard coupled to the reciever signal to esc but because this device started to leak it did not stop the motor as supposed. It is also sticking out of the board and could potentially hurt so I removed it. Now I rely on that the motor stops when I release the trigger or that the reciever loose contact with the tx because I hold it under water. It seems to work fine and it is nice not to have the rope around the foot. Does anybody think this is unsafe or have the experience that the esc do not stop when it loose contact with tx so that the board could go away and hit possibly somebody?.
It depends on the inplementation on the reciver side, but it should work. In my lab setup I added an additional hall sensor to the receiver side. Magnet in front of hall sensor=OK. If the magnet is removed, the thortle slows down to 0. With a strong magnet it should work through the lid of the electronic campartment. Even if you pull the trigger, it stops the foil from running away as soon as you fall off and remove the magnet. Haven‘t tested in practice though.