Gotta agree with everyone that Survivors Can See Infected Ladders is NOT an advantage, except that its Infected Ladder for The Normal Ladder Replacement 'cause the infected will got confused due to new Infected Ladders
NO. VAC FAQ said material modify and config script not BAN. and This add-on is legal vpk file. Propably you dont know VPK file mechanism. L4D2 problem is sv_pure server cvar not working. This is Valve Developer side problem.
AND i think no advantage "Survivors can see InfectedLadder".