In my experience as an HR Business Partner an "immediate" termination is rare. Most businesses will do an investigation into the alleged activity and allow the employee to state their side of the story prior to separating them. Acts that would warrant an investigation would include violating policies or the Code of Business Conduct. Examples would include theft, violations of the substance abuse policy, sexual harassment, lying about sales results or expenses, etc. The bottom line is this: The only thing in your career that is100% in your control is your integrity. Don't ever compromise it for anything and you will not be in a position to be immediately terminated. Make sure you understand your employer's policies and if you have any doubt if an action will be problematic, ask your supervisor or an HR Manager.