It's true you don't need qualifications to sail your
own boat, but as soon as you try hiring one (even a dinghy) they want to see the bits of paper, at least they do in the UK. Not sure about places like Greece. You can take a flotilla holiday there with no-one on the boat having any previous experience at all, but the lead boat shepards such crews very carefully whilst letting the more experienced crews have a bit of fun - at least that's what Sailing Holidays did.
Another place you can go with no qualifications is on our hills & mountains and plenty of people get in trouble there though stupidy and/or ignorance. But again, would you want it any other way? Do you want some jobs-worth checking your paperwork before you can get past the gatehouse and onto the fells? The Mountain Rescue teams certainly don't - and like the RNLI they receive no government funding. The helicopter crews seem to regard it as training and
AFAIK all their services are still FOC both on land and at sea.