“See Pricing, Services and Device brochures, T-Mobile HotSpot@Home Terms and Conditions, and T-Mobile’s Terms and Conditions (including mandatory arbitration) for additional rate plan information, charges for features and services, and restrictions and details, including important emergency 9-1-1 limitations of this service.”

From one of their web pages.

But their sites are all still messed up. I’ll have to check back later to try and find the Terms and Services.