It's unlikely, but I suppose it's possible that if Atlanta gets the #3 pick and can't make up their minds, they'd consider trading it to Phoenix. Phoenix would give back the 2008 pick (of course), one of their later picks in the 2007 draft, and some other compensation. In other words, they'd be changing the protection from "top three" to "top two" on the spur of the moment, with other candies to make up the difference.
The advantage for Atlanta -- again, assuming there's no one they really want at #3 -- is that then they would have their own 2008 pick back and would have more flexibility in making trades during the season.