modifying vending skill

[serverkid]

will this make the vendor immune to monster's attacks?

case MC_VENDING:
if (sd) {
//Prevent vending of GMs with unnecessary Level to trade/drop. [skotlex]
if ( !pc_can_give_items(sd) )
clif->skill_fail(sd,skill_id,USESKILL_FAIL_LEVEL,0);
else {
sd->state.prevend = sd->state.workinprogress = 3;
sd->state.monster_ignore = 1;  //will this work?
clif->openvendingreq(sd,2+skill_lv);
}
}
break;