But I'd also point out that there is somewhat of a logical progression to the point a diver starts seriously learning to wreck dive, cave dive, etc. I'll be the first one to say that I was probably not 100% ready for my wreck training experience. I did my sidemount and wreck training pretty much in tandem, and the wrecks I started on weren't highly complicated, but in retrospect, they were VERY dangerous for that reason alone.
And I think I should have completed all my sidemount training prior, because the challenges of learning to manage air between two 2nd stages, handling bottles as you pass thru restrictions, etc is at least for me, a little much to learn in the dark, 30 meters down. It was so much overload I abandoned my gopro into my second dive and didn't pick it back up until my fifth when I was feeling less task overloading.
Also, we were 'led' thru our wreck dives in a small group and a divemaster that knew the wreck back and forth. There were two or three groups diving the wreck at the same time. But no lines were used, no arrows, and we did some restrictions that were probably questionable considering that I was the only person besides my instructor and the divemaster who was either wreck qualified or in training. Several of our divers weren't even AOW.
For my training, the instructor and I peeled off for 15-20 minutes to do taskwork, lay line, install markers, etc.. then recover them, and other items. But the point is that not one of the other divers out of this group was wreck trained.
Now, maybe some people think the Coron wrecks are pretty innocuous as wrecks go, but of the 8 I dove, six had at least some out of light penetration where the ability to see an exit point was either fully obscured, or behind a steel wall. At one point I was in total darkness, facing a restriction I felt was smaller than I liked, but I was also last in line and the other divers (all smaller than me) had passed thru leaving me alone. I was at 100 dives that day, enough to know I would be all right if I just followed my training. But what would have been the result if that little lady with 10 total dives (three of them on these wrecks in the previous days), had faced the same problem?
So, if you are going to get wreck training, make sure you've already followed a logical sequence to getting there. And always remember that dive operators obviously care about safety, but money talks, and if they think they can get you thru a dive to make a buck, they will.
I know I look back on that week fondly. My dive buddies were great, my training was awesome, but reflecting on whether the dive teams that went thru those wrecks were a wise decision? That's a whole other story. And with the increase in Chinese divers in Asia, and especially Coron, this practice is just an accident waiting to happen.