Every one into photography has their own style and preference.
Unless you are going the professional road or doing photograpgy for
money (that is to sell and make people satisfied with parting their
money for your photos), every photographer can should not be
limited to what the book or the instructor says. Some people tends
to have shaky hands and that explains why a fraction of a second's
difference in the shutter speed can result in one guy taking a
photo with some blurs while the other will not at the same shutter
speed. Not only in photography, in game and shooting competitions
too. You need a stable hand as part of the theory to achieve an
accurate and steady shot on the target. Perhaps if you are trained
professionally please quote the course or manual dictating that. If
its just grumble or a thing the instructor had in his mind then
trainees like you (as we all here know by now) should dismiss that
and observe safety as the top first priority before you can even
tinkle with photography.
If a neck strap should never be used, why are neckstraps still
manufactured and seen with many photographers? If your friend fell
down the Grand Canyon, its his fate or carelessness. Everyday many
corpse are pushed to the morgue. No matter what you do observe
saftey procedures. If you are rushed in a job and almost had an
accident, i don't see why it should be related to someone who are
just taking photos at his own pace? Tell your instructor to get
more rest and take care of his own health. If his too old for the
job just quit.