I have had a quick look at some of the posts. When I see a leashed dog I usually leash my dog and sometimes have a quick word with the other owner to establish the state of play as it were.
As to picking dogs up, yes I have done that with a toy poodle I was looking after when a very aggressive large dog broke its harness and charged and was intent on tearing it apart. I just kept presenting my back with the small dog held tightly to my chest untill the owner gained control.
I chose to do this because a friend of mine was walking her papillion on leash and when a large GSD charged from across the street and she thought it best not to pick her dog up and it was killed instantly when the GSD grabbed and shook it to death. The GSD was euthanaised and it was pretty tragic all round. The papillion did nothing provocative, it was terrified, the GSD was just in kill mode.