So hold the end of the line at all times and pick up the slack? Will Maisy not just feel like she is on a lead walk the whole time?
I would let it trail.... as you say, she cannot behave as if off lead when it is being held, and she would not be able to play with other dogs, so that defeats the purpose...
This is how the long line is used for this purpose (recall away from other dogs) at the training school we use. In other situations it may be appropriate to hold the line (if you are setting up a known chase/aggression situation so you want immediate control, for example) but for general use it is normally advised that you leave the line trailing - it just means you have 10metres of rope to grab hold of to guide your dog back in once you need to stop play rather than having to try and grab the dog (which turns into a fantastic game of chase for your dog!).
The video Seaangler linked to is a lovely illustration of not moving too fast when training a recall command - when the dogs were distracted by the squirrel, the owner was advised not to even attempt to call the dogs, but wait until they were going to be receptive again...
Yes, some dogs behave differently on a long-line (Honey is one of them) and if you have a dog that behaves perfectly on a long-line but turns deaf the second it is removed, many people on here have had success with gradually chopping 1 foot off the end of the line every few days so the dog doesn't realise the weight is reducing.
