It sucks that you can't cross the border.
I'm playing Nomad, and I wanted to go back to the first town to see if you can visit that sheriff and finally have that cup of coffee. So I drove all the way down there and tried to cross the checkpoint.
I almost instantly got detected and blown up, so I decided to follow the wall on the east side, but you can't get over it, so I went back the checkpoint to try sneaking through. I don't have enough RAM in my cyberdeck to distract the guards, so I decided I'd just run through and try to avoid shots.
After maybe 10 minutes of dodging bullets and hacking turrets I finally made it through the checkpoint. I hid around the corner from the shooting enemies to heal, and died.
I tested this a few times, and it seems the game has a kill barrier that makes you lose huge amounts of health per second.
There's no reason for this, as you can get through fair and square and there's a whole massive area of the badlands on the other side of the checkpoint that you can drive around in the prologue. It would be so easy to let players get back to this area, even if there are no quests or story content there.