Players are, in effect, properties. It isn't just about their talent, but their contracts. Would you rather buy a two bedroom house for $100,000 (David DeJesus) or a three bedroom house in the same neighborhood for $250,000 (Lance Berkman)?
Even without considering his contract, Jose Guillen is close to valueless on the trade market, so don't wear yourself out thinking of trade scenarios involving him.
Ditto Scott Podsednik.
Along the lines of #1, prospects and pre-arbitration players are extremely valuable, and teams realize this now more than ever.
It is always possible that one team, even the Royals, could blatantly rip off another, but keep in mind that Dayton Moore already runs the Royals.