It would appear then that the rubber fitting will break before the glue, hypalon or where the hypalon is attached. That then indicates it would require some v serious forces to do damage. So it would be very unlikely that an average sized rib (6.5m say) would not do any damage to another if it tied on to the rubber cleats, unless it was blowing a gale and or a big swell was slamming the boats around.
So whilst yachties are happy for others to moor alongside and use eachothers deck cleats, are some ribnetters being a little oversensitive about their precious boats in some circumstances?
(obvious stupidity re size of boat, conditions of weather and tide excluded)