The problem is you dont know what you dont know...
What I mean is this:
When you first take the "Intro" or "discover" resort class it's not always possible to tell if you have a quality instructor. Perhaps other folks do, but when I went through such a course in Hawaii I was convinced it was a quality and safe experience ( and in fact, I came through safe and excited about getting fully certified).
I was at a top notch resort, and the personell seemed professional, thorough, and competent.
However -- Now with the benefit of more training (OW, AOW and Rescue) and hindsight I realize that I was at risk and that my instructor cut alot of corners.
I'm certain that the majority of resort intro's are safe and the instructors are concientious folks but it's hard to know if you have precious little knowledge about safe diving before you start.
Several Co-workers have mentioned taking these dives and I've encouraged them to get certified before they go, or at the very least do what MikeD already suggested... Take the course and do the poolwoork at home, then do the Open water dives on vacation.
I'm still new and learning, but I'm very surprised at how unprepared and unsafe I was on that Intro dive.
OSB