[baconner]

That's assuming you didn't already tell them about the limitations of the environment they're choosing and explain stuff like ie compatibility modes that can let them move forward but still use all their cruddy old ie6 only enterprise apps, etc. My experience with this is you want them, cut features out if on those old browser versions and periodically remind them that they're holding themselves back. The scenario where they force vendor a to use ie6 and allow vendor b to use chrome IMO doesn't exist if you discuss this stuff up front.