i took the cleats off my laser because I never use them and they are right where you sit and a ratchet block like a fredrickson provides plenty of friction so there is low pressure on the sheet where you hold it
I don't see the problem with cleating the main occasionally while sailing. There has always been a macho thing that you should never cleat your main, but there is really no problem with doing so, as long as it isn't just being lazy. It's much easier to adjust various controls without holding the sheet and it's not as if it is difficult to pop the sheet out of a cam cleat.
It is incredibly rare to see any top sailors without cleats.
I agree that the can come in use as a last resort, but should deffinately not be relied upon on a regular basis. I have come across many situations where they could be used, from tightening your hiking strap to adjusting your outhaul, ( I have the old rigging: ( ). And now with extremely small cams they make they might not be that much of a pain in the rump...litterally. In photos of the Laser Worlds at Hyannis last year, all the boat I saw came with the mini cams.
I regularly use my micro-cleats in heavy air when I need to adjust my grip on the mainsheet. I often wrap the sheet around my hand and play it over the about 1 foot range I can comfortably manage by bending my elbow. When the wind changes enough, that I want to shift the adjustment range in or out (or if my hiking position changes significantly), I'll briefly cleat the sheet while I rearrange my grip on the sheet.
I occasionally use the cleats in *very* light air when I want to avoid inadvertently shaking the sail and destroying the attached flow. It's especially helpful when I'm trying to carefully shift my weight not to have to worry about accidently tugging on the sheet.
I'm using a 1/4" mainsheet, and it cleats great in the small size Ronstan cleats. Sometimes I sit on them, but it's not been a major problem.