There was an interesting post on Sactown Royalty about Ron Artest that applies equally well to the Clippers and Maggette. The gist: the nature of the Early Termination Option is that until July 1, Maggette is for all intents and purposes a free agent and therefore untradeable, since he could choose to terminate the current contract at any point until that time. (The same applies for Brand of course, but is less relevant as there will be lots of trade talk around Maggette and hopefully none around Brand.)
So what? Well, all those proposed trades will have to wait until at least July 1, putting the kaibash on a major draft day deal. Of course, nothing precludes discussing a deal prior to the June 24th draft, and then executing it in July. But it does complicate matters. For instance, if a 2008 draft pick swap is the kicker that gets a Maggette for Calderon deal done, and the Clippers draft for the Raptors need at 7 while the Raptors draft for the Clippers need at 17, there's always the possibility that Maggette changes his mind and stays with the Clippers, and now each team is stuck with the wrong pick. I'll reiterate that it's not impossible - the Rudy Gay for Shane Battier trade in 2006 was conceived before the draft but executed after (hat tip to SR reader and sometime CN Citizen pookeyguru for that one). But you can see how it makes things stickier.
Given that the assumption has always been that Maggette would opt out, and that any potential trade would therefore be after he signs a new deal, we already knew any trade would happen after the draft. The seven pick could still be packaged with him, but the Clippers will probably be making that pick on their own. It's certainly another reason to consider the old 'best player available'.