The fact of the matter is that you can be fired for this reason, any reason or no reason at all (with or without notice). In an "at will" employment relationship, an employer has great discretion in setting the terms and conditions of the workplace; this includes matters how often background checksare conducted and, more importantly, if and when to terminate an employee. For their part, an employee can choose to work for an employer or not.Absent an employment contract or union agreement that prohibits such action, or if any of this violates your employer's own company policy, or this treatment is the result of actionable discrimination, no law is being violated.