Definitely use two screws minimum to secure foot hook. Not always possible without modification depending on insert block location on board. Adjustable stabilizer or mast tracks usually help make this possible.
Well I was considering using foot hooks for a while, but now, after reading this thread, not so much. I hadn't previously thought of the crow bar effect of only one end being attached, but thinking about it, it's a pretty obvious shortcoming.
Been using one regular front NSI foothook for a couple years now on probably 3-5 different boards epoxy resin and poly laminations with just the nsi peel and stick 2 screw female pad in Lto R pattern (rail to rail)and only had one screw/washer pull thru foothook foam never any issues with the deck glass lamination.I only use them occasionally on water start never jumping and occasional handle for a body drag to deeper water,and getting thru smaller waves whitewater,hard to imagine them pulling thru a embedded glassed in insert.work pretty decent actually,was actually thinking of glassing a embed insert on my next board but the peel and stick are pretty stout strong 3M glue on them.