If they're really, really doing this, hats off to them. But you know... there's usually a way. Like maybe they can't budge on the salary number, but maybe a hiring bonus gets a little larger, stock grants/options a little bigger...
Like I said, if they're really doing this, that's great. But are they really committed enough to this to let a great candidate go when the non-negotiable number is too low? Is this just for peon-level employees, or executives too? That's the real test.
Reddit might be a unique case because of "passion hires" -- like gaming studios. People will take far less than market rate if they are working on a project they are passionate about.
That said, I suspect "outside signaling" will become a huge thing. You tell your recruiter you need $X, your recruiter tells Reddit that you need $X, you get offered $X, how convenient for both you and Reddit! On the executive side, over dinner you discuss what it would take you to leave your current company -- of course, not negotiating, just two people talking -- and low and behold, the offer will be exactly what was discussed, of course, no negotiating.
I'm not sure Reddit truly qualifies as a "passion hire" environment anymore to be perfectly honest.
They've been subtly undermining the original promise of the site in various ways. /r/Undelete is a good example of one symptom of the problem. They need to figure out a different way of structuring Reddit's moderation and stop trying to sugar coat things that are clearly financial decisions. The timing of the announcement seems more angled to cash in on sympathy for Ellen Pao than it is an honest desire to "solve" the salary negotiation gap. She has been working with Reddit since 2013, after all.
If it was born from honest desire, they'd have done it sooner and they'd do it like Buffer does [with a transparent salary position list]. The way they've done it they can still pretend there is no negotiation even when they've created a clear loophole for them to make "exceptions".
This isn't so much to attack the way this was handled but more to point out Reddit now engages in the kind of corporate doublespeak that people who are passionate seek to avoid.
Like I said, if they're really doing this, that's great. But are they really committed enough to this to let a great candidate go when the non-negotiable number is too low? Is this just for peon-level employees, or executives too? That's the real test.