If you're not a party to a conversation, then one-party rules don't apply. I.e., in one-party States you can record any conversation to which you are a party,

If you're not a party to a conversation, then one-party rules don't apply. I.e., in one-party States you can record any conversation to which you are a party, but you can't eavesdrop on conversations that you're NOT a party to. This means you can't leave a microphone at a bus stop to record random conversations, say, not without a) owning the bus stop, and b) loudly announcing the presence of the microphone to all users of said bus stop. Replace "bus stop" with any public space. This also applies to private spaces as well, even when you're the owner. Thus you can have video surveillance at any office, but audio surveillance is generally a big no-no.