Ian Mitchell, a maths teacher at Rainham school for girls in Gillingham, Kent, said it was a tragic shame that staff were increasingly reluctant to supervise youngsters on outings for fear of being blamed if something went wrong.
He said: "I am very aware that this story could have had a much less happy ending, but I would hate to think it might stop other schools wanting to organise such trips.
"Young people gain so much physically, mentally and socially from taking part in extra-curricular activities and with proper supervision in place, incidents like this are fortunately very rare."
Mr Mitchell, an experienced mountaineer, was praised for his bravery and quick-thinking when Holly Ashdown, a 16-year-old pupil, skidded off a slope an tumbled more than 60 feet down a forested mountainside in Passo Tonale, Italy.
Miraculously, a tree branch caught on to her skis and she ended up suspended on the sheer edge of a cliff.
Mr Mitchell, 46, quickly collected the scarves of the other pupils and created a makeshift rope by tying them together.
Holly was then supported by the teacher for nearly two hours, until emergency services were able to rescue her by helicopter.
Representatives of the ski firm have since demanded an urgent overhaul of safety netting on the green (novice-level) run where Holly fell.
Headteacher Pat Gunner said: "The school is extremely relieved that Holly and the staff who helped to rescue her were unharmed.
"The bravery of Holly and the four people who climbed down to her certainly prevented what could have been a fatal accident. All the staff with Holly were experienced skiers and she could not have been in better hands."