@Doubletrouble99 - people trafficking was one element of my point. I actually think there is a much bigger issue here.
In the short term, your point has some merit, but overtime the widening gap of political and policy mis-alignment would cause too many problems for no border to exist.
Let me throw a scenario at you, what happens if in 18 months/24 months Ireland joins Shengen? One of the main reasons Ireland hasn't done this already is to honour the Common Travel Area agreement - if that is undermined by Brexit, then Ireland has no reason to maintain that stance, as the CTA's integrity is already breached.
How soon would those Calais Camps close up with everyone heading for Ireland?
What if Ireland was to alter it's migration policy for non-EU citizens given them much easier access to Ireland and therefore the UK.
As I implied, the UK would become a defacto extension of Ireland because their foreign/migration policy is one we would have imposed on us without any say.
There are lots of bizarre scenarios that would play out that absolutely demand a border - which if we are honest, is what us Brexiteers want so that we can control our borders.
If the cost of that is NI with a border in the sea - then so be it.