UCP

#include <amxmodx>
#include <amxmisc>

#define PLUGIN "Block MOTD"
#define VERSION "1.0"
#define AUTHOR "Ser_UFL/Sn!ff3r/TTuCTOH"

new cvar, bool:saw[33]

public plugin_init()  
{
    register_plugin(PLUGIN, VERSION, AUTHOR)
    
    register_message(get_user_msgid("MOTD"), "message_MOTD")
    
    cvar = register_cvar("amx_disable_motd", "1")
}

public client_putinserver(id)
{
    new aid[32]
    get_user_authid (id, aid, 31 )
    
    if (!(containi(aid,"UCP_")))   // или как там ид выглядит?  Если у него id не UCP_.... блокируем закрытие motd
        set_task(1.0, "MotdBlock", id, "", 0, "a", 100)

    saw[id] = false
}

public message_MOTD(const MsgId, const MsgDest, const MsgEntity)
{
    new aid[32]
    get_user_authid (id, aid, 31 )
    if(!saw[MsgEntity] && get_pcvar_num(cvar) && (containi(aid,"UCP_"))) // Если же id UCP_ и квар 1, то убираем
    {
        if(get_msg_arg_int(1) == 1)
        {
            saw[MsgEntity] = true
            return PLUGIN_HANDLED
        }        
    }
    return PLUGIN_CONTINUE
}

public MotdBlock(id)
    show_motd(id, "motd.txt", "RULES")

] setinfo  
*ucp_id             9A6768F71

#include <amxmodx>
#include <amxmisc>
#include <ucp>

public client_authorized(id){
    new sucpid[32]
    get_user_authid2(id, sucpid, sizeof(sucpid)-1)
    log_amx ("Vash UCP ID: %s",sucpid)
    return PLUGIN_CONTINUE
}