Y'know, strangely enough, the only reason I even thought about the divers beneath me is because of some recent threads in the Accidents forum! There were several comments about a dive fatality in which the recovered diver still had on his weight belt. (I believe it was the San Diego diver, who appears to have gotten caught in kelp.) There were discussions about why he didn't ditch his weights, and how oftentimes recovered divers still have on their weights, and why don't they ditch them? And several people mentioned that there are hazards to ditching weights when divers may be below them. This was actually the first time I'd heard that - I don't recall that coming up in my OW or AOW classes - but it stuck in my head enough so that it flashed across my mind before I reached for that belt. The other team of divers really were right beneath me - we all did our blue-water safety stops together, and I would have felt horrible if I KILLED somebody by dropping lead on their heads! And then I had air and was getting help to remain afloat, so it became a non-issue.
That's what I've usually done. I've never actually checked my reg & computer - I carry them in their nice padded carrying case. The problem for this trip was that it was a 3-week tour to Machu Picchu and the Galapagos with multiple stops (Lima, Cusco, Aqua Caliente, Quito, Galapagos), which included train trips and small-plane rides and four days on a small ship with very limited luggage allowances. Plus, there were two climates I had to pack for - up at 12,000 ft in the Andes is COLD, and then we had our week at the equator, which was HOT! AND we wanted to leave at least SOME room for souvenirs! All in all it was a very challenging trip to pack for, and as it was I had a large and heavy carry-on (in addition to my at-the-limit checked luggage). The rental gear was included in the quoted price of the dives - we didn't save any money by bringing our own - so we elected to take the chance and rent.
But after this experience, I will be bringing my own stuff wherever I go.
Shipping could be an option, if it's not somewhere remote and off-the-beaten-path, like Galapagos! I'd hate to ship it out and have it not arrive in time. And then what...ship it back? How long would all that take? I'd rather keep my gear with me, and just pay the luggage overage fee, if necessary.
In any case, this was an odd confluence of situations that I hope to not encounter again. Frankly I'm thinking of staying home for a while!