The thing with the borders is the immigration rules, Scotland needs roughly 200,000 immigrants a year to fund the pensions and welfare bills. This as the SNP have stated will mean no rules on incoming immigrants.
When you look at the immigrant population, is says something to the UK that the biggest immigrant population is the English (Not even the Irish), even though the Irish have an entire Quango dedicated to looking after irish concerns.
what will happen, is thousands will fly to Scotland and walk into England without Border controls, presently there is free passage between Ireland and Eire, this is entirely due to the similar immigration policy.
The debate has transcended usual political / religious beliefs, Irish Catholics are voting No, and Scottish Protestants are voting Yes.
Anyone who doubts my comments on how it is here, you tube Jim Murphy.
Look at the houses attacked, Cars attacked for displaying a no sticker.
Having said that I have No stickers on my car, however friends have told me to remove them Friday, it's going to be hellish in Scotland on Friday