or the rebellious fled beyond Rome’s reach, as with the Scotts and Irish.
The Scots weren't in Scotland in Roman times, they were (or rather, their ancestors were) cowering in Ireland, wetting their kilts in fear. After the Romans left Britain for good, the Scots still didn't start to settle in Caledonia and conquer and absorb the Picts for a century or so.
There's evidence (see the links) that the Romans established a trading presence in Ireland, btw.