No it isn't. Katrina's surge where the eye came ashore was 28-30 feet. No one is predicting this for Ike. I am not taking sides in the debate of who should flee and who can safely stay: we are all responsible for our own decisions, and no one who isn't physically present with long-standing familiarity with the place is qualified to offer a judgment about what course is best. TRP, this veteran of Betsy, Gustav, and countless storms in between salutes you and wishes you all the best from New Orleans.
You are missing a key aspect here. Galveston Bay funnels the surge, akin to what the Bay of Fundy does to tides. If the surge is 16-20 feet at Galveston, it will be much higher at the head of the bay. THAT is the danger. And since there has not been a storm like this in recent history - Carla hit well down the coast, whereas this storm is forecast to strike just SW of Galveston and is geographically huge - a worst-case strike for surge - they really can't be sure of what is going to happen. That is the entire point - they UNDERFORECAST Katrina. And people died as a result - it wasn't the fault of the forecasters, it's just that, if you are counting on five feet of elevation as your safety margin, that is foolhardy.
Well God Bless you! I was there that weekend, ya know, Katrina weekend. Evacuating cut my weekend short and it ticked me off bad. I had reservations at Brigsten’s that Saturday night and was not at all wanting to leave. But I did. I’ll see NOLA in December :-) as I do every year. We missed our summer trip there this year because we were both retiring.