The phrase "don’t worry they’re friendly", is wishful thinking. Jumping up is an annoying and potentially dangerous behavior in dogs. Every dog is a potential weapon. There is always a first time when a dog bites or knocks over a person warranting first aid treatment or replacement of soiled/torn/damaged clothing.
One needs a permit to possess a gun/weapon. Therefore it should be law that dog owners prove their competence in handling their dogs.
The best advice I can give, is to stand completely still when a boisterous (untrained) dog approaches, hands wrapped around one's upper body, and as already mentioned, lift up one knee to ward off the dog, avoiding eye contact, and refraining from speaking or touching them. The dog is expecting a reaction, any reaction, positive or negative.
Some breeds like Jack Russell Terriers, Border Collies, and Golden Retrievers, are often enthusiastic greeters.
Every dog owner is (actually) aware that their dog's poop must be picked up. Unfortunately, you cannot watch them 24/7, and some irresponsible owners will pretend that it wasn't their dog's poop. Despicable! Getting dog owners to monitor each other, may work if they all cooperate.