The UX is not good enough yet. We would have to 1) show that it is reserved to people going on the link and 2) offer good/enough ways to be notified once the link becomes online and 3) need to know the likelihood of the link to actually work in the future based on prior commitment.
I think the idea is that if you were recording a podcast it wouldn’t be live (I know the parent used the word live but I think they meant “live” during recording or in conversation while the episode is being created), so you are free to make references to soon to be declared URLs.
You just have to make sure you have populated the content at the location you are referencing before you upload or publish your episode for your listeners.
...and URLs being forever cuts both ways. Want to reorganize your domain's structure? Better set up 301s to forward the old address, forever, and hope (or avoid) any overlap between the old schema and the new.
Transfer of ownership? Well, all those hyperlinks from other sites don't know.
AND I probably forgot a couple of issues.