First, this could be a prudent response to a lot of bad things happening and asking power system operators to not do anything that could remove more generation or transmission from the systems. After all....Thursday's warning came as a heat wave swept through Nevada, Arizona and New Mexico. Two large nuclear power plants in California, Diablo Canyon and San Onofre, were closed for routine maintenance. There also was a disruption in a north-south transmission line, said ISO spokesman Gregg Fishman.
On a second perspective, California could be nervious anytime they get close to load resource balance as somebody, say BC Hdyro, could watch and then pull the plug on them. There are lots of organizations that would enjoy watching Cal-ISO go down. California may not want to be close enough to the ragged edge of service that they are beholding to any one entity that they have mistreated in the past.
On a Third level, the Davis Administration may feel that blackouts are its equivalent to the Bush Administration war on terrorism. That is the the California public may rally around the Governor in a time of obvious crisis and that Davis may be able to improve his standing with the public if he helps people through a time of crisis.
After having gotten the three alternatives off my chest, I vote for item 1 and a hmmmm for item 2 (possible but not probable).