1. The domain is likely transfer locked and it's a bug in the registrar's availability detection triggered by the DNS outage

2. Even if it wasn't, Facebook could follow the UDRP process to get it back.

If you were holding it to ransom and threatening them with an outage the length of the UDRP process that might be extortion but if you just bought it out of curiousity and it went through and you handed it back it'd probably end up just like the guy who got google domains to "sell" him google.com a few years back

https://finance.yahoo.com/news/guy-bought-google-com-google-...

I think the ICANN dispute division would retake ownership of the domain and give it back to Facebook.

https://www.icann.org/resources/pages/help/dndr/udrp-en

No worries. You would never make it that far. You would not ever take ownership of the domain, so Facebook would never need to "retake ownership".

This is like going to a garage sale and someone tells you that they can broker a deal for the original Mona Lisa for for just $59 plus a 10% commission. But when the broker calls the owner of the Mona Lisa they inform you that its not for sale.

In this case, the registrar is trying to sell its domain brokering services. When you search a domain they either will sell you the domain, or if the domain is not available, they will sell you a service where they try to broker the domain for you. Now of course when they call up Facebook to see if they want to sell the domain, Facebook will just say no and the conversation will be over. You are out $59, which was the flat fee to initiate the brokering.

The phrase "I've got a bridge to sell you" comes to mind... I don't think the buyer would be in any particular legal risk. The right question to ask is "will I be able to get a refund after falling for this obviously fraudulent / mistaken listing."

An organization like facebook doesn't go down in a day. The domain name (and, presumably, associated trademarks) would almost certainly be auctioned off in a highly publicized event.