Charity fundraisers are being urged not to venture on to mountains unprepared.
Many climbers are ill prepared and cannot read maps
Cumbria's Wasdale Mountain Rescue Team was called out five times from Thursday night to Sunday morning to help people attempting the Three Peaks challenge.
The task involves climbing the highest mountains in Scotland, England and Wales - Ben Nevis, Scafell Pike and Snowdon - in 24 hours.
Rescuers said many of those taking part lack basic navigation skills, such as reading a map and compass.
Bill Pattison is the president of Wasdale Mountain Rescue Team, having retired as team leader after 22 years. He said he had had concerns for 20 years.
He said whilst many of the bigger charities ran properly organised events, there were smaller groups who were not properly prepared and mountain rescue teams were having to act as "unpaid guides".
"What they are being asked to do is go up and sort problems which could have been avoided if they could navigate.
"A particular worry is that they will be so tied up with this, if someone had a bad mountain accident, they wouldn't be in a position to respond", he said.
One of the problems was people's reliance on mobile phones and their feeling that if they had one they were safe but that did not compensate for a lack of navigation skills.