So does Twillio... not surprising at all when there's no encryption and they need to debug real phone calls routed all over the world which is not an easy task.

As long as they're only spot checking and not browsing through any one persons calls for no reason I don't see why it's a big deal. It's mostly business lines anyway.

That said, they should have some protocols and controls in place for listening to any calls, with solid paper trails. Every company like that should have a privacy manager to direct and monitor these measures. They could even document/blog about their work on privacy for marketing purposes (assuming the executives are aware of just how in-demand privacy has become these days).