I have been on a boat where most people were using rental gear not equipped with depth gauges (or of course computers) and the divemasters told people on the boat afterwards that they had been to 130ft and it was a recreational dive. I was with the group all the time and I recorded 145ft, and my computer showed several minutes of deco. In fact, one of my two computers was still in deco when I surfaced with the other divers and I was heavily criticised by the boat captain for setting a bad example by going into deco. The truth was of course that everyone was in deco but no-one else was wearing a computer (no, not even the dive leader) but didn't know it!
Not equipped with
depth gauges??? That sounds...that's
insane! I've never heard of anyone going on a dive without a depth gauge -- that's gotta violate PADI standards, doesn't it? I mean, no computer, ya...I've never received a computer on rental gear. But without a depth gauge you can't even use tables to calculate your dive plan. I would never set fin in the water without a depth gauge. And for such a deep dive too! That's nuts.
A similar thing happened to me at the Blue Hole as you are describing above: I'd brought my own gear, and had my computer, whereas everyone else in the group had rental gear with no computer (although they DID have depth gauges), and was doing their dive based on the DM's computer. When we ascended, my computer gave me 8 minutes of deco time...which the DM was REALLY pissed about! He wanted me to abandon my deco time and surface after 3 minutes, but I refused (hey, it's MY body...and this would have put my computer into tilt, and we still had several days of diving ahead of us). When I boarded, he started yelling at me - but I told him to stuff it, because I'd done the exact same profile as everyone else, so clearly everyone else had a deco obligation as well. I wasn't surprised that I went into deco - due to a couple of inexperienced divers in the group panicking at depth, we ended up staying down there for a couple minutes longer than the plan.
It's just another reason why I question the overall safety of all of these operators who do the Blue Hole - they all apparently take inexperienced divers, in too-large groups, with questionable profiles. I guess it's just the nature of the business there.
But back to whether or not someone should dive the Blue Hole - I personally am very glad I did it...and like everyone else, I probably wouldn't do it again. But it's important to understand that the reason it's a one-time-only dive is not because it's not worth dong - IMO it is - but because the view doesn't change. Unlike reef dives, where you never know what fantastic marine creatures you might encounter, the view at the Blue Hole doesn't change. Once you've seen it, there's no real reason to go to all the trouble (and expense) to see it again.
If I go to Belize again I would probably do a BH dive trip, and skip the BH dive, just so I could do Lighthouse Reef again. They were the best dives for our entire time in Belize!