Live strattle Question

[parisron]

Everywhere I have ever played including most of the casinos in Las Vegas. When a Live Strattle is made the dealer makes the anouncement loudly to the table "Live Strattle" usually before the last card is dealt to the button. But here in Tampa at the Hard Rock, the dealers only anounce it before they are done dealing about half the time. Most of them probably are not used to the concept since they just started doing it along with the new NL games on July 1st. My question is, Is it a rule that the anouncement of "Live Strattle" has to be made by the dealer before the last card is dealt or is it just a courtesy?