Certainly so, Scrump and Cap'n. I did a degree in classical singing, so I understand your misgivings. However, a PA that's well set-up (and that's the important issue here) in a quiet room can be very useful depending on what style you're performing. Sometimes the intimacy you can gain from almost whispering on the mic is more appropriate than having to project. Horses for courses. What is much harder to listen to is those usually acoustic performers who haven't learned mic technique and constantly distort and "pop" due to being too close.

The question remains - does the open mic session equate with the 1970s contemporary clubs? I'm not sure, but I'd say there may be a difference in intention. A 70s singer-songwriter club might tolerate a serious traddie getting up to sing a 25 verse unaccompanied ballad, but I seriously doubt the same could apply to many open mic nights.