When you are training recall, reward every single time she comes back. She needs to build the association between returning/arriving back with you and getting the reward.
If she's not reliably coming back, it is easier to have her on a long-line so you can reinforce the cue, as you're right, repeating the cue is undermining the 'I call once - you come straight back to me' message. You don't hold the long-line, you let them run and trail it behind them, then you can stand on it if it looks like she's gone recall-deaf and is heading off on her own agenda.
I would do things slightly different to how Mistle does it. I'd call her back, put your hand in her collar, put on her lead, treat, then re-release. That stops any negative associations with the lead being put on, as you do it whether she is going to be released to play again or not and she gets the treat after the lead is clipped on. Otherwise you end up with a dog that does the annoying 'you can't catch me' dance, just out of arm's length if they see their lead come out of your pocket or your thumb on the clasp. (I had never really thought that much about this before, but this is the way they do it at Pip's puppy classes and it makes a lot of sense to me.)
Do lots and lots ... and lots of call-collar-leash-treat-releases, at home in the garden, as well as during every walk and try to minimise the level of distraction if possible, then build it up gradually. If she's ignoring you when there's something more interesting going on, she's not reliable enough for that level of freedom just yet and you need to go back a couple of steps in your training to where she was reliable, reinforce that, then move on to higher distraction levels very slowly (only moving up a level when you'd happily bet money she'll return).
You only shift onto intermittent rewards when she is spot on with her recall. It sounds counter-intuitive I know, but it actually makes them keener, as they never know when to expect a super duper treat, so they have to keep trying their best, whereas if they get something lovely every time, they tend to get a bit blase about rushing back to you, as they know they'll get it anyway.
Pip's recall has gone a bit wobbly now he's hit the hormonal stage, so I'm going through a similar process at the moment.
As for being mugged by other dogs. Being a veggie, I hate having dog food in my pockets, but also hate the bum-bags that some dog walkers use, so I bought a very cheap canvas across the body bag off ebay a bit like this and use that. It's been really useful, as I can fit poo bags, hand cleaner, my mobile, clicker and extra treats in the back section and I use the front section for top-grade treats. I use tie handle sandwich bags to keep the treats in and then when I'm not using them they can be tied up and zipped shut, which helps keep the smell under control. I wear mine either across-body style or round my waist, depending on what sort of walk we're on and whether or not I mind looking like a green wellie brigade dog-obsessed numpty! 
I had to cut the flap off my bag because it was in the way at dog club, so something like this might be better.