[Alienmario]

If someone comes looking for this like I did, here's my working solution.

PHP Code:

public OnEntityCreated(entity, const String:classname[]){
    if(!StrContains(classname, "item_")){
        //SDKHook(entity, SDKHook_SetTransmit, SetTransmitItems); //uncomment to hide items
        SDKHook(entity, SDKHook_Touch, StartTouch);
    }
}

public Action:SetTransmitItems(ent, client){
    if(ClientsThatCantPickUpItems[client]) return Plugin_Handled;
    return Plugin_Continue;
}

public Action:StartTouch(ent, other){
    if(other<=MAXPLAYERS && ClientsThatCantPickUpItems[other])  return Plugin_Handled;
    return Plugin_Continue;
}