Request: Prevent an addon from firing its script on reload?

[Aethereality]

Howdy. I'm trying to write an overly basic addon that runs some code when the player first logs in, but not when they do a /reload. Is there a way to prevent this from happening?

The code is very basic;

local frame=CreateFrame("Frame");
frame:RegisterEvent("PLAYER_LOGIN");
frame:SetScript("OnEvent",function(self,event,...)
    --My code is here, it's one line
end);