There was a thread going on this same topic a while back with a lot of interesting points:
http://www.walkhighlands.co.uk/Forum/viewtopic.php?f=1&t=29620&st=0&sk=t&sd=aBut very recently (Sunday) I had an experience where I really did have to insist that I change someone's plans for them. I'd parked at Linn of Dee, cycled to White Bridge, dumped my bike and walked the round of Beinn Bhrotain, Mondah Mor, Angel's Peak, Carn Toul and the Devils Point. Then down to Corrour Bothy and walked back to White Bridge. It was midway on this section that I came across a sight I'd never seen before: two women out in the wilderness, one of them without any shoes or boots on! All she had was little sports ankle socks on and as a result was caked in mud, with her ankles and feet cut to ribbons. She'd lost them in a bog a few miles back and couldn't retrieve them.
When I started speaking to them they said their plan was the Derry Loop, starting and ending in Linn of Dee, they were only about 8kms in with another 15kms to go, it was after 4pm and they were moving insanely slowly (obviously) and were already exhausted. The more I got out of them the more I realised that even ignoring the missing shoes they were quite ill equipped for the sort of terrain they were getting themselves into. They told me they had no maps, no torches and it didn't look like their packs would've contained what they'd need to complete their walk without incident. The lady WITH shoes had done the route before was very keen to continue, so was driving the lady WITHOUT the shoes pretty hard as I think she was aware the day was getting on. However she didn't realise just how far they still had to go, I got the impression they were thinking they only had a few miles left.
I took out my map, showed them where they were and where they still had to go, indicating that it was pretty rough mountain territory for someone with shoes, let alone someone without! The leader was still undecided and I could see that she wanted to go on but her shoeless friend was unsure. So being quite authoritative I pretty much insisted that their only option at this point was to turn back as they'd definitely be walking out in the dark, so at least it would be on a path they already knew having spent the last 4/5 hours walking it!
Now I may have come across as a know-it-all d**k, however I was genuinely concerned for the safety of the women without shoes on. It would've taken very little for her to break an ankle in that sort of ground. After turning them round I went off and kept checking that they were following me, and they were, albeit very slowly. So I put on the pace, got to my bike and belted back to Linn of Dee to get a mobile reception (this took me about 90mins WITH shoes, moving fast and using a bike). Once I got phone reception I called 101 non emergency police and told them about the incident, and that while they weren't in immediate peril, they weren't in the greatest of situations and someone should be aware of where they were. They called me later on, after 9pm, to say that Ballatar Police Mountain Rescue had picked them up near White Bridge safely, thanking me for my call.
This was the first time I've ever put the pressure on someone to change their plans, but I genuinely felt they were walking themselves into danger and without a map could've easily taken a wrong turn and ended up in the Larig Ghru or somewhere else they didn't want to be. An extreme case, but one worth sharing I think.