Seems to me that leaving a boat unattended is very much an "it depends" situation. Shorelines are steep where I dive, so I'm never more than a longish swim from land. Loss of the boat is a far bigger risk than loss of divers around here.
Even so, I wouldn't dive without a boat tender in areas where current picks up or steep walls prevent securing an anchor. On the other hand, I've not had a tender on a lot of dives where we anchored in 15' in an enclosed bay on a mud bottom.
Even so, I wouldn't dive without a boat tender in areas where current picks up or steep walls prevent securing an anchor. On the other hand, I've not had a tender on a lot of dives where we anchored in 15' in an enclosed bay on a mud bottom.