Reasonable on 20 September 2008
It's not mandatory yet to include them... although I believe it will be throughout 2009.
Therefore right now its down to developers own choice - some are clearly stepping up to the plate, while others aren't willing to invest the extra time/effort.
Some choices do seem surprising - for example I note Fallout 3 may not have them while the Bioshock developers are including them and seem to have gone out of their way to make Bioshock a success on PS3.
Try to be reasonable... its easier than you think...
