You have to deal with the limitations of having a reactive dog I'm afraid.. you know the situations where she is ok - so you have to stick to them.
You have no control over other people and how they train, or don't train, their dogs. You only have control over the situations that you put your own dog into.
I have a reactive rescue dog - and I have had to change my dog walking habits to accommodate that fact. For 20yrs I walked in the most gorgeous woodland. I haven't been there in 7 yrs because I can't do that with this dog - too many off lead dogs, narrow tracks, blind corners, bushes, so I can't see who's coming. I only walk in places where I have a very good line of sight and can see who is coming, no interesting new places, just the same predictable walk, round the same park, at the same time, meeting the same dogs. I know which ones he will go for so I know when to go in the other direction.
I am responsible for my dog, you are responsible for yours. Accept the dog you've got, accept the limitations that come with having a reactive, there's absolutely no point getting wound up about people who have nice friendly dogs who like to socialise - they haven't a clue, unless they've had a reactive themselves - and then they WOULD be trying to get theirs on a lead!
Apart from anything else it's just not fair to the dog to keep putting them in situations that cause huge stress - it reinforces the problem.