I worked at a place for 7 years as a developer. I gave 2+ weeks notice. I was immediately bolted to another dev and we began the brain drain on getting that person (more senior) up to date on all my systems. I retained full access to all of the systems I had prior. I was removed from all new dev work and was a "reference point" for the remaining developer base for the remainder of my time.
A DBA at the same place left about a year after. He didn't make it back to his desk before he was given his boxes.He was paid to "not work" from home. Part of that was risk aversion, because of his production access and part of it was his everyday attitude.
If you show yourself to be low risk, you will be treated as such. It is in the company's best interest to siphon off as much knowledge at possible, but not at the expense of a disgruntled employee with production access.
The comments about "locking file-shares and emails" was silly. If you are doing pre-delivery archiving and server file system level backups, you're doing it wrong.