I suspect they actually do expect them to burn-up on re-entry... but by telling the FAA they may splashdown, it absolves them of any problems if for whatever reason they fail to fully do so. And then the public communication has to match what they told the FAA.
They would normally have to do a debris analysis. I would expect them to burn up, because we'll have a real problem if Starlink satellites start surviving reentry. But it's possible that since this is a very low injection point and speeds will be lower that some parts might survive. If they do, it makes Starship survival look less impressive though...
