This is the intriguing thing and something I have puzzled over. If the guys with the beards showed up with intent for business, there is absolutely nothing that anyone would be able to do. The beards are in charge immediately. But the fact seems to be that the guys with the beards do not show up in Algeria when one is accompanied by Algerian guides. Why? One set of possibilities (and this was behind my initial comment) is:
1) the guides sign up responsibility for the tourists (this is a fact)
2) the authorities make it clear to the guides that the guides have this responsibility and that there are consequences if things go wrong (this is quoted as being the case by some who have acted as guides). I don't know any more details about this.
3) this is the big jump in logic + without any evidence - the bearded ones may not want to put the guides in a position where consequences are imposed on them - so they don't take from guided parties in Algeria.

Why is (3) true? Only because it seems to be the case that it is true. To uncover the background to this claim is to get into the heart of the AQ-M relationship with local people. AQ-M are raging the state and the west but not the locals. From where I am sitting they seem to have strict codes by which they work. The lack of action in the desert in Algeria may be an indication of these codes at work. One kidnapping of a guided party in DZ is all that it takes to wash away point (3). I'm not meaning to tempt fate.....