If the applicant does not expose their skeletons and the employer finds them, the applicant either does not get the job or the applicant is terminated from the job if already given the job. This is a double edge sword.
There's worse things in life. Also, at many companies once your in...your covered by a collective bargaining unit (union), etc. All one has to say is he/she forgot about it/it was a sealed or expunged record, etc.