In reply to blackcat: I do agree in some ways, but not in others.
I think if your dog stays by your side and your on big easy paths, then your fine, but most dogs that go out on the hills, tend to be lively so like you said could get themselves into risk .
Id rather leave my dog at home (and this is what im going to do) than keep him on the lead all the time, and in winter, this could be a lot around difficult terrain!
Like you id happily risk my life trying to rescue a dog, and id hate to be the person who caused all that.
I think im going to stick to summer stuff, and even then if i do anything near crags hell have a harness on, and in winter at most ill do none craggy easy stuff.
Id love for him to come into gullies, i know hed manage easier than me, he can certainly climb better than me! But its not fair on him, or others when/if it goes tits up, and ive no interest in him being on a lead for long periods, hed be miserable!