The supervisor is instructed to walk the employee to a conference room where HR is waiting. While the employee is being informed their IT systems access is being locked (in the desktop days the keyboard was removed). Once informed, having received an information package, and having been given the opportunity to sign a exit NDA type document (required to receive a severance package) the supervisor is asked to escort the person to their desk to gather the minimal amount of personal items (keys, phone, wallet, purse) and then escort them out the door. The supervisor or the department head is responsible for having the persons remaining personal items boxed and shipped to their home address. Supervisors are suggested not to clean out the office or cube immediately as to not give a bad impression. In a large workforce reduction event the manager level supervisor lets their staff go over a period of a day or two, then senior management lets the manager go in the same fashion. Directors, AVPs, and VPs are treated slightly differently but are not immune to layoff.
This is a calculated process by design; to mitigate conversations that might result in legal actions later, to mitigate the employee from doing any harm or damage to information or property, and to avoid public displays of emotion which can send other employees into panic. Most often the word has spread days or weeks prior that something is up, security intensifies, and during the process people are parked in their offices and cubes calling out a play by play, person by person using IM.
If you can honestly say you brought it every day, did a great job, and produced success then being layed off has absolutely nothing to do with you and everything to do with how leadership failed to perform. The only exception to leadership failure would be if your position was a direct labor position i.e. tied to a contract and the contract was ended by the customer.
Hold your head high, be proud of what you've accomplished, and be excited to find the next chapter in your career. That and don't live above your means while you are employed so you can ride through bumps like this.