Q: I live in Gretna, work in Carlisle - will I need a passport every day?
A: No. Same as someone living in Letterkenny (Ireland) and working in Derry (NI) today. CTA = live and work anywhere. No passport. Ever. 103 years.
Q: Will army put checkpoints on A1?
A: No. Illegal under CTA. UK and Scotland would both have to agree to leave CTA. Neither will. It would be political suicide for any English PM to demand passports for Scots visiting family in England.
Q: What about smuggling?
A: Same as now between NI and Republic - some smuggling of diesel, cigarettes already happens. Police deal with it, not army checkpoints. Has done for 100 years.
Q: If Scotland in EU and England out, will I get stopped for bringing shopping from Berwick?
A: No. Personal shopping not customs. Same as you can bring €2,000 of stuff from Dublin to London now, no one stops your car.