What is your point Rroff ?
If the disable switch was not put in then there would not be no need for any discussion on the matter.
There are valid technical reasons for not running the resolve code on unsupported hardware... that said I do take issue with the fact that its not presented under some kinda advanced menu as an unsupported option.
My point is that saying "nVidia disabled AA on ATI cards in Batman AA" is mis-guided at best as its implying intent on the part of nVidia and mostly used as a way to attack nVidia.
To again highlight my point if we take mass effect 2 as an example... another game thats based on the same engine as Batman AA and has the same issues with AA but ships with no AA support at all... now say the developer approached ATI and nVidia and asked them to help implement AA on their respective hardware and ATI complied and presented working code but nVidia dawdled and didn't have anything to offer by the time the game shipped... and then reviewers noticed that on ATI hardware the game had the option to enable AA but on nVidia the option was missing... wouldn't the nVidia crowd look a bit silly baying about how ATI had disabled AA on nVidia cards?