https://www.theguardian.com/us-news/2021...nise-the-number

Hiker lost on US mountain ignored calls from rescuers because he didn’t recognise the number

Summary: they sent two rescue teams after him that didn't find him. He was lost for around 24h before finding his own way back to his car, with no idea that anyone had been looking for him.
Quote:

“One notable take-away is that the subject ignored repeated phone calls from us because they didn’t recognise the number,” the agency added.

“If you’re overdue according to your itinerary, and you start getting repeated calls from an unknown number, please answer the phone; it may be a search and rescue team trying to confirm you’re safe!”