The only time I've ever signed or ever will sign a mechanics lien waiver was when I was picking up a check from a contractor. I have in the past signed a partial lien waiver on large projects that were done in phases, but I was also collecting a partial paycheck at the time. I would never sign one at beginning of a contract before getting paid. You might as well wear a sign on your back that says "screw me in the butt"
This is CABL.com posting #203984. Tiny Link: cabl.co/m1ee