I do sometimes use a stern "Ah!" and it does have some effect. But I have to find a better way of getting her attention in those situations. Because if I cannot get her to snap out of her frenzied behaviour and focus on me, I can also not distract her and get her to focus on something else. If I start the distraction early enough it does work. I have absolutely no problem with the 'look at that' method when we are visiting somewhere with little kids. But I don't really want to do the same with every person we meet and she manages to take me by surprise often.
She does not care people ignoring her at all when she does it. The jumping itself is the reward. But she is so enthusiastic that she always does get a reaction anyway.
She knows she is not allowed to jump up on us. Still tries sometimes when we come home, but we just walk out again and close the door and then the second try is always successful. We can use the same method with guests that come to our house, but obviously it does not work when we are out walking.
So I am still experimenting with what works and what doesn't. With my old dog it used to be chasing that was the issue because once she had taken that first stride towards her 'prey' she did not hear me anymore. With Banjo the preparation to jump is enough to block any external impulses getting through.
Wow, sorry, I was really just thinking out loud there. I'll probably come back to read this thread in a little while and have a lightbulb moment.