The dogs and I went on a fairly stiff walk on Sunday (Pen-y-Ghent in the Yorkshire Dales) as part of our training for tackling the Three Yorkshire Peaks at the end of May. My dogs always wear limited slip collars which prevent them backing out, and with no buckles that could accidentally pop/release or break. Very strong collars that carry all the necessary ID (I love these ones http://www.lupinepet.com/).
I walk with a rucksack plus waistbelt and a carabiner, the dogs wear their walking/running harnesses (http://www.ruffwear.com/Web-Master-Harness) and the leash clips to my waist keeping my hands free. The other beauty of this system is that even if they did escape the harnesses (very unlikely!) they still have collars on.
While resting on a handy patch of grass near the car park a gorgeous young dog came by (a Northern Inuit I think) on a harness much like mine, flexi leash and with two runners. The dog was interested in my two but everyone was very polite and they headed on to their car.
Next moment - the young husky-type comes bounding over and rather exuberantly says hello. Clearly the harness was removed to get dog into car and the smart dog took the opportunity to escape.... Cue a good ten minutes of chaos as the husky-type got more and more into the game of avoiding his handler, made much easier by the fact that the dog wasn't wearing a collar. The whole situation eventually ended when one of the runners rugby-tackled the dog. Not a great way to maintain your relationship and could have been so easily prevented....
You might have noticed that many dogs are actually not that keen on having their collars grabbed, especially if we don't give them much warning. We work round this in training class by teaching all the dogs that the cue word "collar" means we're touching the collar + a tasty treat is delivered. We work up to practicing grabbing the collar as you might need to in real life and making it all part of a really fun game. So if your pup or dog doesn't like being touched on the neck/collar and is telling you - why not reframe the whole experience for both of you and see it as a training opportunity!