Jerricho,
There was a test program going on at Houston for a while allowing the departures to exceed 250, but that ended some months back, and I doubt it will return.
tired,
I can only imagine that West Coast is correct. The controllers want you at 280 kts as soon as legally possible. They just don't use 20 words to say it always. It's also legal some distance from shore, but my memory fails me at the moment. (Don't get the opportunity to use that loophole)