[dctoedt]

> One can imagine lots of things that have an incidental effect on exercising the right to bargain collectively; I don't think the NRLA can be read as preempting all of those things.

I dunno about that — my guess is that Congress intended a heavy presumption: Anything that materially diminishes the right to concerted action is unlawful. I know, materiality will often be hotly contested. Here, though, an employer's ability to unilaterally take away one of employees' key enforcement weapons, viz., the class action, seems pretty freakin' material.