It's highly unusual to allow a person with high access to remain on the premises after giving notice. Even if management follows the general procedure of removing access, someone who has worked for many years in a trusted position of authority may very well have alternate means of gaining access. Physical access to the premises, following someone who has recognized your face for many years into a secured data center is not that difficult in many corporations. Standard security policy for any security conscious company upon receiving someone's notice typically involves a short exit interview. During the exit interview all access to systems get revoked, while management explains the severance package, unused holidays, paying the employee 2-4 weeks to not come in... After the exit interview security can escort the person off the premises.

When I left IBM to pursue a life worthwhile, I was well aware of how they dealt with folks who intend on giving notice. I knew when I planned to leave and started working on finishing my active projects that could be finished and bringing in more of my employees to co-develop on the projects that would continue to exist after my departure. A couple of key trustworthy developers I clued in to my general departure plan. I did not inform anyone of my specific departure date, in order to give them plausible deniablity.

Management saw me as a wonderful mentor. When I did turn in my notice, I did it on a Friday as I was walking out the door. I came back in on Monday with an escort to officially say goodbye. To my knowledge, everything continued to operate normally without the guy who never got to take any vacation because he was critical to the success of the business.

It was a win win. The corporation had trained personnel in place to continue without disrupted services. I left knowing that any of the projects I had any emotional vested energy would be properly looked after. I happily cashed the paychecks they sent without a twinge of guilt.