Hi all!
I think I should state the reason why I've posted this question:
Basically, our public safety rescue diving organization requires using a security line to the surface and buddy lines under water. This applies to all search and recovery operations, as well as to all training dives. So all rescue divers of my squad are generally using buddy lines whenever we go diving, even in diving sessions "just for fun".
Sometimes I go diving with recreational divers who don't like the buddy line. However, I did already some dives without buddy line, but in my opinion it's more comfortable to use one. You can just look around and enjoy the environment without watching your buddy throughout the dive. You can be sure to advise your buddy immediately in case of problems. Plus, you can be sure not to get lost if you e.g. become a victim of sudden cardiac arrest.
As most of you've written, it depends on the sight whether a buddy line can be useful or not. In the Lake Constance, there are very steep slopes and rock walls down to 300ft. Plus, in summer sight is often limited to the glasses of your mask. It's completely dark in 50ft. In 2000, we had two fatal diving accidents over here. Both bodies were found after some days of search operations. No doubt, if they wouldn't have been lost by their buddies, they could have had better chances in resuscitation. No matter what their initial problem was.
Thus I'm just interested in recreational diver's opinions. I'm planning to do some tests regarding the danger to get pulled up or down by the buddy in case of troubles.
Thanks for answering my questions, so far.
Happy new year!
Andre