|Presidential guard soldiers are seen on the grounds of the Laico Hotel in Ouagadougou, Burkina Faso, Sept. 20, 2015|
This is not terribly surprising that the RSP does not want to disarm. It stepped down in exchange for the safety of its members and their families. Protestors are calling for leaders of the coup to be executed. One reason military governments are willing to negotiate their exit, as the RSP did, is because they can enforce conditions such as amnesty for the coup because the military holds weapons. Geddes notes that "Militaries can enforce compliance with amnesties and other deals, but only if they can make credible threats to respond with violence if the new government reneges."
If the RSP disarms, it will be relying on the words of last week's agreement. Since the RSP, whose mission is to protect the president, instead overthrew the (interim) president and put him in prison, they likely put little stock in the constraints of mere words.