Is it legislated to say "peace be upon you" to a person of unknown religion?

Scholars differ on the permissibility of initiating greetings of peace with a non-believer. The majority opinion is that it is not permissible, based on the Prophet’s (peace be upon him) saying: "Do not initiate greetings of peace with Jews and Christians." Others hold it permissible, citing evidence that is open to interpretation. The first opinion is more cautious and more absolving of responsibility.

If the person's status is unknown, and the majority of the people in the land are Muslims, it is permissible to greet them with peace. And if you pass by a gathering that includes Muslims and polytheists, it is permissible to greet them with peace.