Youcantparkthere - were the children guided to the correct destination with hands on their shoulders (acceptable, in my book) or were they roughly hauled around by their arms/collars (not acceptable)?
It's worth knowing that it always looks bad when the account of an incident gets more extreme as a thread goes on - it looks as if you are trying to play up the seriousness of the incident in order to get those who have disagreed with you, to change their views.
I would suggest, on a purely practical level, that you volunteer to help with some school outings/class activities, because it is a whole lot harder than getting your own child to do what you need them to. You will find that children don't listen to everything the teacher says, they miss some of the details of the instructions, or forget what you've said, or get distracted from what you are saying by new surroundings (like the church, full of parents and other school children and with lots of interesting things to look at). If you try to get the children where they need to be by just talking nicely to them, it could all degenerate into utter bedlam.
I used to help out in ds2's class, when he was in year 2, and I well remember the day when I was trying to help just 8 children fill in a maths worksheet. None of them had listened to and remembered all the instructions, and as soon as the first one went wrong, and I had to get them back 'on task', the seven others round the table used that time to go wrong as well, in many different ways. And that was just 8 children, one of whom was mine, and should have been used to listening to what I was saying!
What I am trying to say is that it is vastly different trying, with a limited number of adult helpers, to get a class of small, easily distracted children, to go in the right direction, and if you'd tried to do it yourself, you might have a little more understanding of the TA, and of what she was doing.
Someone described it as like trying to herd cats, and they are not far off, ime.