Scam ID works a bit like caller ID: If a call comes from a number the network suspects is predatory (cross-referenced with PrivacyStar's database of known scammers), the customer's phone will display a "Scam Likely" alert. If they don't even want to take the risk, users can turn on Scam Block to prevent those shady calls from making it to their device. T-Mobile has already identified and flagged or blocked 273 million of these calls, according to the company's press release. Given how obnoxious robocalls are -- and how much money they can cost the unwary -- any effort carriers make is welcome.