My Aunt Ruth(less) attempted to murder her mentally retarded sister with insulin and did time. Later on she applied for a job at a nursing home and failed to check the box about prior felony convictions. Got the job anyway. My father-in-law was in the hospital at the time and we were terrified when Ruth, who was visiting, changed his IV.

She tried to end a patient at the nursing home and was also busted for raiding the medicine cabinet. Obviously no check.

My son applied for a job at a small construction firm and they did call his references.