[Cidrei]

Assuming you're referring to BadBoy_Levels (going from the level 100 mention), search for "Ambiguate" in BadBoy_Levels.lua and two lines down replace

if good[trimmedPlayer] or trimmedPlayer:find("%-") or UnitIsInMyGuild(trimmedPlayer) then return end

with

if good[trimmedPlayer] or UnitIsInMyGuild(trimmedPlayer) then return end

That should allow blocking of cross-realm players as well, though I haven't tested this. There may be a reason cross-realm players are explicitly allowed.