[Face9000]

pawn Код:

if(newstate==PLAYER_STATE_PASSENGER)
{
  switch (GetPlayerWeapon(playerid))
    {
      case 24,27,31: //WEAPONS IDS
      {
        SendClientMessage(playerid, 0xFFFFFF, "You can't driveby with this weapon.");
        SetPlayerArmedWeapon(playerid, 0);
        }
    }
}

This goes OnPlayerStateChange.

Sorry for bad ident.