I love Cialdini, thanks for linking. I recommend his book on Influence to everyone.

I did think about this reciprocity initially when I heard no equity involved, however I don't think YC & Co's problem is getting startups to agree take their money after mentoring? Their issue is likely getting enough investment opportunities to put cash into as fast as they can raise it. ( ie-pretty fast ). For that they need a bigger opportunity pipeline.

So, i basically agree that they are getting first dibs, but due little to Cialdini's rule on reciprocity. I'd point more towards 'Liking' (ie building the trust early) or 'Authority' since they are getting in the door first with founders and are likely the initial startup mentor.

What I see, is that this program is just a simple (relative) way to ignite some ideas that are on the cusp of being implemented, remove some of the founding barriers, and start a conversation with their team earlier on in the process (no one wants to be the third on the list to call to invest in a great co.). The standard YC class schedule and size limitations are likely the gating factors to their growth, especially when interest in 'startup investing' isn't declining, and YC has already made moves to make it easier for non-accredited investors to invest.

Maybe this is in line with what you were referring to.

It will be up to the wider community to educate the young impressionable kids who take the money that they have no obligations to YC and that there is no such thing as loyalty in the valley. YC is sure as hell gong to chuck them to the road if they don't work out.

Unfortunately a lot of these kids will probably feel guilt over taking the money and feel like they have some kind of obligation to take deals that are much worse for them.