The main reason archaeologists have nothing to fear from booby traps isn't that the machines have been buried a couple millennia. It's that the ancients just didn't have cool machines like automatic door closers or trip-wired blowguns or enormous ball returns. Archaeologists know this both because they have never found the ball returns but also because the ancients didn't brag about them. If Pharaoh Amunhotep XXIII had something like that, or thought of it, or had somebody on the Cool Weapons staff who thought of it, there would be stellae (upright inscribed stones) trumpeting his total coolness and showing giant bowling balls knocking down Midianites like squishy duckpins.
The whole article, true to Straight Dope style, is educational and entertaining: