My neighbor had three dogs. One named Millie. Millie is an incredibly sweet and good mannered dog. Apparently she also has a 6'+ vertical...
She can do this from the side of the fence without poles or crossbeams, but then apparently can't figure out how to get back into her yard. She'll do this, wander around in the alley, and when I go into the alley will go right to her back gate to wait for me to let her back into the neighbors yard.
Or she'll walk around the end of the block, go to my neighbors front door and wait there for him. I told him he needs to install a doorbell on a button at snout height and teach her to press it when she comes around. heh
My border collie was like that when he was young. I put him in my grandmother's back yard which has a 6 foot fence just like that one thinking he couldn't get out of it. I went into her house and before I even got my coat off, he was standing at her front door wanting to come in. I took him back to the yard and told him to jump the fence just to see if he could actually do it and he didn't even hesitate.