Traditionally, SETI is not specialized to messages intentionally crafted for us (or, in fact, necessarily crafted for anyone). It's just a search for radio transmissions that are unlikely to have been created by natural sources using various statistical techniques.
Even for intentional messages, it's certainly conceivable that another civilization with sufficient power simply transmits the message in all direction continuously.
Even for intentional messages, it's certainly conceivable that another civilization with sufficient power simply transmits the message in all direction continuously.