hi,
last year i had a middle ear squeeze during a max dive attempt. at around 35 mt on hte descent i felt this sudden pain and turned around. i clearly remember i didn't have any warning of that. this is also what i told my buddies later (alun might remember that because we were diving togheter that day). well, i've been thinking a lot about that, and i got to the conclusion that i must have had a warning, but i was not aware of that. i was going for a max depth, and i was focused on my target, and probably i was a bit stressed out because i didn't feel like doing a deep dive that day, and i just failed to notice what was coming.
sometimes i dive with people who claim they don't have contractions during their dives, but i can clearly see their diaphragm spasming. how's possible? that's lack of awarness.(i went through the same at the beginning of my deep diving career!)
or people kicking their fins togheter, and say that's impossible. or people losing air from their mask during descents, and saying they are sure they don't.
i might be wrong, but i'm rather sure that majority of divers don't break their eardrums on an easy 20 mt recreational dive, when they are relaxed and aware of themselves, but rather on a deep and demanding one, when they are stressed and unaware.
as for reverse block, so far i've never seen anybody getting a sudden serious reverse block without warning, but it's rather a feeling building up one dive after the other. so a sensible thing to do would be stopping the diving for that day and avoiding it to get worse.
(hey, i don't want to lecture anybody here, i'm just offering an explanation)
cheers,
linda