I feel I need to defend myself a little here, even though I have already admitted unreasonableness!
She is a nice gentle dog and not snappy, but can get a bit overexcited when given attention (she acts like she is starved of affection and therefore grateful for any!). I walk her in appropriate places, keeping her on the lead the majority of the time, apart from when it is acceptable to be let off. She doesn't run off or run up to people at all at these times, she stays close and either plays fetch or sniffs everything in sight. I always ALWAYS clear up her poo!
Where we live is quite rural and there are an awful lot of dogs. Many are not on leads, and it is incredibly common to see them tied up outside the village shop, surgery and school. I have taken her on the school run in the past to collect my DC1 and waited outside with her for my DC to come out. My DC2 started at the school last term and so I need to go into the playground to collect them. No more than a handful of times I have taken the dog on the school run since DC2 started.
There are lots of dogs at the school and most are tied up or loose by the gate. I personally have never liked them being so close to the gate as you cannot avoid them, they are just there. As an aside, I once asked a woman to move her dog at the local park because it was a huge mastiff and tied to the only entrance to the park and it was really intimidating.
I will admit to not having given the situation a whole lot of thought, but given that it is the norm to be walking to school with the dog and tying it up at the fence it didn't really occur to me that it was such a terrible thing to do - I stand corrected now! Because I don't like people being forced into an encounter with a dog, I have tied my dog up well away from people. You would really have to make an effort to go out of your way to get to her.
So to clarify, with hindsight I freely admit that IWBU to leave my dog unattended for a few minutes in what I thought was a reasonable location. I won't be doing it again now that I have read this thread and considered the points raised.
However, I do think it is a sensible, common sense approach to teach your children not to approach/touch/flap your arms at(!) any animals unless you have asked permission of the owner and I do think that people do need to take a bit of personal responsibility here too. I can honestly say that if any of my DC ran up and grabbed a dog and it snapped at them, I wouldn't be blaming the dog. If they had just been walking past and it had snapped at them unprovoked however, I would feel differently.
I think someone early on compared it to children being taught not to run into the road, but being unpredictable creatures they sometimes do it anyway. With that in mind, if you had taught your child road safety and they ran into the road and were knocked down by a car, would you instantly blame the driver, or would you accept that the child had made an error of judgement? I'm not trying to cause a row, I am just intrigued as we also saw on the horse thread that personal responsibility comes into play there, so why not with dogs?