These pro-ams are essential to the Tour, but they are a huge problem as well. I don't know exactly how everything works on Tour, but let me clarify a few things about these pro-ams.
1) Players don't choose to play in them, they're assigned. Pretty much, the top ranked players each week have to play in the pro-ams. 18 guys in the morning and 18 in the afternoon. I'm not sure if they get any outs, like one freeby a year or something of the sort.
2) When a player no-shows or is a late, another PGA Tour player plays with the group. Typically, there will be 4 players on-site assigned to be there from approximately 6:30-8:30 AM. Then another group of 4 will be there from 11:30-1:30. The players will practice during this time, but are on-call if there's a problem. I'd venture to guess each player on Tour has to be "on-call" 2-4 times per year. It's not that bad.
3) The DQ for missing a pro-am has been around for awhile, but they used to give each player one miss with no penalty. I'm guessing they took that one free miss away? That's too bad because the penalty doesn't fit the crime. It's ridiculous really. After this Furyk fiasco, I bet they make a change this offseason.
I believe the players understand the importance of these pro-ams, as the ams are putting up 5K each or so to play, but they're also pretty rough to play in them. They usually take 5+ hours and it's hard to get much productive practice out of them. That being said, playing with a few ams for the opportunity to play for millions isn't so bad. I'd certainly do it if I could.