Ted Bundy is the poster boy. He escaped custody twice. And when he escaped the second time, innocent people died needlessly. His life revolved around killing and he was tough to keep in custody.
There can be no absolute guarantees when the criminal is in prison; and no doubt; not a perfect night's sleep for potential victims; revisited. .
and of course, there is always the threat of 'mudslides. . .tsunami's. . .earthquakes; hurricanes. . .that just might require evacuation and opportunities for the more determined and desperate.
Better safe. . .than sorry. . .