If Giles steps foot on the court this season and plays say 40+ games and plays reasonably well, i.e. 8-10 pts / 4-5 rebs/ 2 asst / 1.0 blk in 20min/game, then I have no doubt that another team could easily take a chance on him.
Even if the other team offered him a very average contract of 2 years for $10-12 million, that would be $2 million more than what the Kings can give him. For Giles, playing with his knee history, you would think he would jump on the extra $2 million and no one would blame him. A contract like that would be low risk/high reward type gamble we see all the time in the NBA.
That is where the Kings made a very risky and potentially very bad gamble IMHO. If we can buy an extra year at a paltry $4 million option and see what we've got, you have to do it. Its a no brainer to me, unless Giles isn't likely to play again this season. And if that were the case, he shouldn't be listed as Questionable on game day 5 games into the season.