[evgen]

Let's consider the counter-argument and ignore any possibility for vandalism, theft, hacking, or other destructive activity by a recently terminated employee. Why would you want them walking around the building? What possible benefit is there to this? Why not just give them a hearty handshake, a thanks for your work, and tell them that they will be paid for the remainder of the termination period but don't show up at work tomorrow.

As for the paranoia part, it is definitely a bit of paranoia on the part of the company management but paranoia for a reasonable reason: there are numerous examples in the US of someone getting laid off or fired and returning to the office with a gun. From the perspective of management, why take the chance? If there is any hint that the termination will not be pretty you make sure someone escorts the person out and you have shown yourself to be taking due consideration if something unpleasant happens.

[sangnoir]

> What possible benefit is there to this?

Non USian here: regardless of who gave notice, the lame-duck period is normally used for wrapping up whatever work/project the departee was working on and handing it over to a colleague or manager. People generally are more worried about getting bad references than office shootings.