A common sight anywhere there are tourists are the Tourist Police. This group is designed specifically to monitor the tourist areas, deal with any issues, and protect the tourists as they roam around. They are especially common around Giza and the Valley of the Kings (the biggest tourist draws). Our guide told us that they are so visible because the Asian tourists seem to like the presence of the guards, especially after the massacre of German tourists at Hatshepsut's temple in the late 90s. Me? Well, a bunch of armed guys wandering around isn't particularly reassuring, but that's just me.
Sometimes, they can be a bit overwhelming. We had at least four Tourist Police officers with us all the time (usually in a small pickup truck, guns pointed out the windows!) and oftentimes a couple of trucks. When foraying out of Cairo to Middle Egypt, we had "bodyguards" in the van with us and usually picked up a few others on the way.
For awhile, I thought we were the only ones with the "star treatment", since the tour busses didn't seem to attract the attention that we did. But, most independent tourists are tracked quite closely -- at each road stop, the guards wrote down our license number and some other notes about us. A friend who went on a trip later (in 2004) said that they had to report to the tourist police every time they left the bus. SInce we didn't have a bus to track, I guess they glommed on to us.
All the tourist police are armed, and its often hard to tell them from the regular Army soldiers also posted at some of the sites. They are all supposed to speak English (and most do, to some extent), and can be quite helpful if you are lost. We did find quite a few of the Tourist Police expecting tips -- sometimes they were quite pushy -- but this was normally handled by our guide. It seems that it is normal operating procedure to tip the guys who have to follow you out to the sites and wait for you. Since they can't make very much money in salary, this seems pretty fair to me.
Tourist police also man the security stations at some sites and run the metal detectors, etc. We found these at a few places, including the Museum, Abu Simbel temple, Hatshepsut, and in some cases, our hotels.