For those who might be unfamiliar with the law, recording calls might be legal or illegal depending on which state you’re in, and which country you are from. For example, some states in the US have a “one party consent” legal requirement in which it is legal to record a call as long as one of the call’s participants, such as yourself, is aware and consents to it.
Other states have a requirement in which both parties need to explicitly give their consent to be recorded, and as Cult of Mac points out, countries such as Australia and India have banned call recordings entirely. In this particular feature, Apple will allow users to record both regular and FaceTime calls, but they also put a disclaimer in which they warn that users will need to obtain consent first. However, this is more of a guidance rather than a technical requirement.
Like we said, Apple has billed itself as a privacy-focused company so it is rather strange that they would introduce a feature that could knowingly be construed as an invasion of privacy. Needless to say that this should be taken with a massive dose of salt for now, but we’re hoping that this isn’t true.