Originally Posted by
NickB
In the hundreds of times I have travelled between Dublin and Belfast in the last ten years, whether by train or by car, I have yet to be subject to cross-border immigration checks. The only period I was regularly stopped at the border was during the foot and mouth epidemic but the controls were just to check whether animal products were carried rather than for immigration purposes. What would have a greater likelihood of happening is being nipped by the NIPS for a motoring-related offence (eg speeding) or some other non-immigration related random control.
They might be billed as "security checks" or some other thing rather than formal immigration checks. They are also targeted at people deemed likely (presumably by their appearance) not to have the proper papers.