heck we thought a knock sensor would be a good thing to have especially on an H22... why not?
that idea ain't worth a velvet painting of a whale and a dolphin gettin' it on...
the stock knock sensors are generally from my understanding disabled in higher rpm where they are needed, and terribly inaccurate. IIRC the damage is generally done by the time they do anything.
and why do you say especially on an H22? they arent that knock prone, and if you are worried about the ring lands, they arent any worse than most other stock cast pistons, with a good tune they are able to make good power on stock internals. ask spiker about some of his buddies up WA that make good numbers on stock parts.
just go p06, p28, p30, p72 or whatever and save yourself the trouble.