One overlooked issue here is what would have happened had  Petrov decided that the warning was based on an actual attack. It's implicit in many popular accounts of that period that the Soviet leadership would have launched a nuclear attack. I seriously doubt a war would have been started based on a hypothetical go-ahead by Petrov's command.

Despite all the bombast and deliberately deceptive and self-serving declarations by the Reagan administration, there were continuous informal encounters between the two nations, not only the Harriman meeting in May. In the conflict between Schultz and the hardliners, Reagan preferred the former for dealing concretely with the Soviets while using hardliner tactics and language in the public arena.

Further the Petrov event happened only weeks after the downing of the KAL flight which the Soviets genuinely perceived as an American reconnaissance mission. They were very much hurting from their own fumbled handling of the incident's aftermath in the following propaganda war launched by Reagan. The entire command chain responsible for the incident were demoted and transferred shortly after. The incident was perceived as a serious flaw in Soviet defences. That Petrov's unit was also reprimanded makes perfect sense in light of Soviet defence vulnerability and plain military logic.

The KAL downing also eclipsed Soviet overtures to the West over the deployment of the Pershing missiles. The Soviets had not only put a moratorium on the deployment of SS-20's but had formally declared that the Soviet Union would never launch a first strike attack. The Soviets certainly lost the propaganda war at the time, yet another vulnerability in their system, despite the fact that the Reagan campaign over the KAL incident was based on knowingly manipulated evidence. But the bottom line in the war of words was not who was insane and a liar but how the two nations could get back to negotiating a new détente. In that optic, any surprise attack was totally off the wall.

Arguing from "what-if" scenarios is difficult. However, despite public ostentation of war-like attitudes, both contendents were aware that nuclear war was a totally irrational option not only for themselves but for their rival.

Petrov did his job well and can be commended for it.