Does the beep legally function as informing the other party? Would it be illegal to record voicemail without the beep? Would be cool if the government created

Does the beep legally function as informing the other party? Would it be illegal to record voicemail without the beep? Would be cool if the government created a "recording consent" sound, so you could play it in lieu of spending 5 seconds to explain that you'll be recording. I suspect a beep does not qualify in most situations, would need to be more distinctive. Saying "leave your message after the beep" seems unambiguous, but are fake messages where someone pretends to answer the phone in a legal gray area? (I'd guess voicemail is a legally-ambiguous loophole that was grandfathered in because so much of the population understands it, but curious)