Well, a couple points come to mind.
Often our guests on our dive boats refer to me as the DM. Unless they have had specific reason to know otherwise they have no way of knowing my certification level. There are times, even when I am teaching, that I perform some common DM duties as a part of the boat crew. Perhaps this was some sort of an instructor/student situation, or it could have been a DM/certified diver (possibly as student) situation.
Isn't it most common to begin the dive into the current? That's the way I run dives unless we have specifically briefed a drift dive.
It sounds as if closer buddy contact would have been more desirable in this case, but I don't have enough information to form any opinion about other issues.