And before ACA, the prospective employee would normally have to show evidence of continuous creditable coverage before being added to the new employer group pla

And before ACA, the prospective employee would normally have to show evidence of continuous creditable coverage before being added to the new employer group plan. This is how pre-existing conditions were handled - if you had always had coverage, OK, but if you went uninsured for a while and then tried to re-join a group, tough luck.