Dude, don't encourage them.
Michael Pachter, industry super-analyst, has a theory about why software sales took a fifteen percent dive last month: We're all too busy playing multiplayer games online to buy the next big thing. Clearly, the only thing that will save game publishers from a fate worse than death would be to start charging players to play online. Since Activision's Call of Duty: Modern Warfare 2 is the biggest game on the market, Pachter believes them to be the clear choice to spearhead such an effort in the industry.
Of course, Activision CEO Bobby Kotick has already had the idea and it's only a matter of time before such things transpire. When (not if) it does, I'm looking forward to the supernova of rage on the internet and declarations from people claiming they'll never buy another Activision game again. Then the industry will move as a whole, such subscription models will become the standard and the vast majority of boycotters will wind up forgetting their lofty ideals. Get a firm grip on your ankles kids, because it's coming.
I would be totally comfortable with such a scheme if I thought for a second that it meant we would pay less for games where the main focus is on a multiplayer experience, with the difference expected to be made up for in online service charges. Instead, we'll probably pay the same prices we do now and get a free month of online play for our specific games.