It wasn't "On Her Majesty's Service" anywhere
I saw it. "MOD property" was the one I
remember.

There are more badge types than three!! 

TO name a few more... There is the green stripe badge with gold 1/3 overlay for "permanent contractors". There is the violet stripe. (More of a sickly wine color, with just a bit of blue grape juice added.) There is the yellow/blue "barber pole" badge. Etc.

And all of them have a form of RFID circuitry built in, don't you know.

This thread just perpetuates the impression that Intel peeps are a bunch of tightasses. 

One pointless article and all these tightwads come out of the woodwork.

Intel has been monitoring its employees for a LONG time, even sending its own security department out to sort through the trash of suspected employees for any clues.

It's an old book, but "Inside Intel" by Tim Jackson (published by HarperCollins) is a really interesting read on this and other Intel subjects, up until 1997. Highly recommended geek reading!

Oliver.

Inside of Intel sites, anyone needs to visibly carry an identification badge above their waist. 
There are three types of badges:
* "blue badge" for regular full-time employees
* "green badge" for contractors regularly working on site
* "pink badge" for visitors and one-time contractors (e.g., the plumber fixing the loo the author went to, or the author himself, for that matter)

While blue and green badges are free to roam wherever they desire, pink badges require to be accompanied at all times. When a pink badge signs in at the frontdesk, a blue badge signs this off and thereby assumes the responsibility for that pink badge following the guidelines while on site. The blue badge is released from their responsibility with the pink badge signing out at the time of leaving the site.

That's just standard procedure. I suppose you were issued a visitor badge. Visitors are supposed to be escorted at all times, which unfortunately means you will be escorted to the bathroom as well. That's so people don't wander around, regardless of whether there are secret materials around or not. Overkill, I know, but Intel keeps some of Grove's paranoia around.

Is anyone else as confused as me after reading this?

I've worked in a few development labs, with stuff that would be released to customers in months (not years), and find cameras covering all work areas and hallways and badge readers at every door (not just external ones). Nobody thinks that anything is private from the company, and we're only a few months away from customer's hands. Intel's labs, I'm sure, work on projects far earlier in the development cycle, of course they are going to want to make sure you're being looked after.