I was listening to a summary of the arguments on the news tonight, and it sounds like the arguments for Walmart fall into "blame the victim" space. It's Walmart's actions that set up other companies for class actions, not the milllion-odd women who are suing.
I actually found myself wondering if the Scalia, et al. are in the pockets of some corporation. Especially if they rule for Walmart right after Citizens United v Federal Election Commission.