I don't know. If 411 wasn't advertised or noted in the contract as a "free" or included feature, I don't see how adding a fee would provide a way out.
That said, I've never even considered 411 since I can look things up plenty fast and accurately on 3G, 4G, or wifi.
In an age of everything's accessible self-service, I anticipate fees for almost anything requiring hands-on assistance.
The sad part is I don't see any breaks coming from self-service. I'm less concerned about my phone carrier than the fact that I don't get any $ back or discount for checking myself out at stores with self-checkout.