Hossa signed with a major rival, hence the booing. Stuart did the same, hence there will be booing. Neither player owed us anything, but we couldn't afford Hossa so Stuart deserves it more than Hossa. Give it 3 years and no one will care anymore, same thing happened to Fedorov.
Oh, there will be. Sad, but true. It'll be the same idiots that boo Hossa when he did nothing but fulfill his obligation, which was a huge risk in the first place given the 1-year term in the prime of his career.
Most people are fans of the team's well being not the players.