[grand.Theft.Otto]

You have to make a variable.

Just pretend this is your minigun game:

pawn Код:

// top of script
new inmg[MAX_PLAYERS]; // mg = minigun (in minigun)

// command

if(strcmp(cmdtext, "/mg", true, 3) == 0)
{
    // give the minigun, send messages, other codes here, blabla
        inmg[playerid] = 1;
        return 1;
}  

// onplayerdeath

    if(GetPlayerWeapon(killerid) == 38 && inmg[playerid] != 1) // 
    { 
    new name[MAX_PLAYER_NAME];
    new str[128];
    GetPlayerName(killerid, name, sizeof(name));
    format(str, sizeof(str),"%s is suspected of having a weapon hack (Minigun).", name);
    SendClientMessageToAdmins(0xFFFFFFAA, string);
    }
    return 1;
}

// ! means NOT as a short form
// != NOT equal to
// so therefore: if they are NOT in mg, it will show, but if they are, it wont show

Hope you understood, let me know if you need help.