This has (or had) real world implications. Back when phone answering machines were a thing, and you could dial a pin number to your own to have it play back mes

This has (or had) real world implications. Back when phone answering machines were a thing, and you could dial a pin number to your own to have it play back messages... well, I remember an article in 2600 (I think) that explained that there was a superpermutation that gives up the goods. It would take up to 3 or 4 minutes to dial in, but eventually you could start hearing the messages. There was some mention of news reporters doing this to the phone numbers of local politicians, but that must have been speculative or outright bullshit (even then there would have been an applicable law against using such an exploit).