DOES A FINAL WARNING OFFER ESTOP EMPLOYER FROM FIRING WORKER?

An employer notifies an employee, who has no prior warnings or offences, of a disciplinary hearing for an alleged serious offence. Before the hearing the employer offers the employee the option of accepting a final warning in return for the employer cancelling the hearing. The employee refuses this offer. At the hearing the employee is found guilty as charged. Is the employer estopped from firing the employee because of its prior offer of a final warning? In providing your view, please take into account that item 2 of Schedule 8 of the LRA states that warnings should be given for less serious offences and dismissal should be reserved for only gross misconduct. Item 4 of Schedule 8 says that the employee should not be dismissed unless his conduct has made continued employment intolerable. Does the fact that the employer previously offered the employee a final warning serve as an admission that the offence was not gross and has not made continued employment intolerable and thus as an estoppel against a dismissal penalty?