I went to Roatan this fall, and I did two weeks of diving, one week from shore and one week from a liveaboard. When I went to set up my gear for that first week, I was horrified to realize I had left my single tank adapter at home, so I could not assemble my BP/W. I had a day before the first scheduled dive, and I had more than a week before the liveaboard. I did everything I could think of to replace that STA or find some other suitable replacement. Employees where I was staying tried to help, calling around the island for anyone who could help me. There is an entire thread in the Roatan section of ScubaBoard detailing my plight.Another thing to consider. One of the top reasons that many get certified is for a single/once-in-a-lifetime vacation dive trip. The BC that is most available in the majority of resorts and dive rental shops is the jacket BC, so it makes more sense for them to have learned in it.
I finally gave up. I rented a jacket BCD at the shore-based operation, the only model they had. Even given a week's notice, the liveaboard was unable to help, and I rented the only BCD they had--a jacket, of course.
The dive operation I regularly used in South Florida did have two, and only two, BP/Ws in their rental gear, so my friends who came to visit were able to use them. All the rest were jacket BCDs. That shop was a GUE instructor development center, and it sold Halcyon gear. The sales floor, however, was dominated by ScubaPro gear, including BCDs and Seawing fins. When my friend lost a fin getting on their boat and we went into the shop to get new fins, we could not find any suitable blade fins with wide sidewalls (needed for some advanced kicks), and we had to go to another shop in town to get a pair.