[Kanegasi]

I posted on your MMOC thread, but I'll answer here as well. UnitCanAttack will filter for hostile or neutral units, and I'm pretty sure you can't attack yourself so your nameplate will be left alone. The nameplate loop logic was also a bit redundant.

function(allstates, event, unit, ...)
    if event == "NAME_PLATE_UNIT_ADDED" then
        if unit then
            local guid = UnitGUID(unit)
            allstates[guid] = {
                changed = true,
                show = false,
                PassUnit = unit,
                glow = false,
            }
        end
    end
    if event == "NAME_PLATE_UNIT_REMOVED" then
        if unit then
            local guid = UnitGUID(unit)
            if allstates[guid] then
                allstates[guid].changed = true
                allstates[guid].PassUnit = "none"
            end
        end
    end
    for i = 1,40 do
        local u = "nameplate"..i
        if UnitExists(u) and UnitCanAttack("player",unit) and
                UnitHealth(u)>=1 and (UnitHealth(u)/UnitHealthMax(u))<.3 then
            allstates[u] = {
                changed = true,
                show = true,
                PassUnit = u,
                glow = true,
            }
        else
            allstates[u] = {
                changed = true,
                show = false,
                PassUnit = "none",
            }
        end
    end
    return true
end