The split that matters
Most US states allow one-party recording consent. A significant minority — commonly counted around a dozen, including California, Florida, Illinois, Pennsylvania, Washington, Massachusetts, and Maryland — require all parties to consent. Counts vary with how each statute is read, which is exactly why operations default to the strictest interpretation rather than maintaining per-state cleverness.
The operational answer: strictest-state by default
When calls cross state lines, the conservative reading applies the stricter state's law. The clean operational posture is a recording notice up front on every call, everywhere. It costs a few seconds of script and removes an entire category of exposure — and it's how Revolv configures campaigns by default.
There's a second-order benefit: if every call is noticed and recorded, then every call can be QA-scored, every disclosure verified, every consent provable. The compliance requirement becomes the foundation of the quality system.