Nobody is saying it's the only way to do things. In USA it's not the only way to do things. It's not only done in USA (I worked in Canada and in Europe, never in USA).

I'm Canadian, it's our national pastime to diss our neighbours to the South, but the notion that a laid off employee can be a high risk to the company knows no borders. Are we making a claim that those working on Rafale or Gripen get to keep messing with classified files after being fired, because "we don't DO that in Europe"? :)

Let me tell it differently. I have seen people fired or laid off and exactly one was taken away immediately. The exact same company fire also different people, without walking them out immediately via security.

I have heard of one more person fired that way - it was by American company and pretty much everyone else treated it as great injustice. Team members met with him in nearby pub pretty much right after.

I've seen this happen to people numerous times in the UK, so it's not only a US thing but may be more common there.