How can I get other people to be consistent with my dogs without sounding pushy?

If people invite her to jump up on them, gently put her off and explain to the person that you don't want her to learn to jump up on people as she may not know the difference between a 90-year old and a 20-year old and you don't want her knocking people over and injuring them. Or you could say you want to use her as a therapy dog and one of the automatic failures is jumping up on the evaluator, and you don't want to set her up for a failure. I find when you explain, people are usually willing to listen. For the ones who aren't, just take your dog and leave.