Next month I will be constructing a second floor ensuite with laundry facilities. I know the hoses you are talking about Nap and they work well. I also investigated the auto shut-offs from Watts. However...a couple of months ago the people upstairs from me were doing the laundry and nobody noticed right away that a small hose INSIDE the washer had come off the nipple. Water was literally gushing out of my potlights in the hallway and also through the ceiling in my storage area. Glad I was home to catch it. Anyway, the only way I can foolproof my project is to install a Fernco drain and extend the flooring Ditra up the walls about 2"
Wow that must have been a shocking sight to see especially if the lights were on! The fun thing about water and electricity is that it also produces oxygen and hydrogen, for added effects.