Jammer,
A few thoughts to consider;
The written evidence is far removed from the supposed events, such that they could equally be judged as rumor, literally inconclusive. The wholesale distruction of relics and names within various tombs however demonstrates personal attacks on the individual or cult. Evidence in the form of tunneling does not explain who did it, it may have been done by the royals as easily as it may have been done by robbers. I find it difficult to imagine that a team of robbers could successfully dig up a tomb without being noticed, the work required would not occur inside of a week but months and perhaps even longer, all for a few items of gold and gems that could easily be got by robbing travelers or caravans along trade routes. Surely we can all agree that early dynasties through the Old Kingdom had economies based solely on the afterlife cultic worship, that the regard for the dead was of the highest order. The sacred lands given for burial is well documented and the divisions of it given to successive generations by royal order. At Giza we see as many as 5 generations involved in some of the mastaba complexs.
I tend to agree that the lawless footprint of the 1st intermediate holds the most prosperous culprits of tomb robbing, those which lay far from centers of habitation. Subsequent robbers may have been looking for secrets more than jewels and gold. On the whole, the fact that some remarkable relics and un-disturbed tombs have been archaeologically discovered in the massive eastern and western mastaba fields at Giza, Saqqara and Abydos, where one could literally dig a simple pit and find goods in ancient times, leaves one to wonder just how rampant tomb robbers were in the first two historical eras.
Clearly efforts within the builders design were conscience of blocking access from intruders, and that the robbers knew exactly where to dig shows a revealing degree of understanding that the subjects had about the location of goods within the tomb. The question however is whether or not they were robbers or under the orders of the royals to retrieve them; perhaps to relocate them to an even more secret location. As an interesting aside we still have no remains of the royals from these eras; were they collectively stashed for protection???
Best Regards,
B.A. Hokom