The bandwidth usage limits are ONLY for Internet.
The reason for bandwith limits are from agreements with other ISP's / network providers, the TV service would never leave the MTS network, so it doesn't have an impact on other providers.
They can differentiate between TV and Internet, and the customer would only be responsible for Internet usage. They used to have a tool online for old internet service, but it doesn't work anymore apparently. I heard that they have to show the customer their bandwidth before they can charge them for it, so I don't think it would be a big issue until then.