How is something consensual unfair? If a person places a low value on their time or a high value on the experience that will be gained, it seems like it might be a reasonable trade. This seems especially true if the person giving up their time isn't in dire straits... i.e. If you offer to pay pennies and breadcrumbs to a starving man, that might not be cool. If you offer a good unpiad experience to a hacker/designer who is otherwise darned employable, it doesn't seem evil at all.
If I lived in the Valley and had an opportunity to hang out at YC dinners in exchange for a bit of free work, there was probably a time in my life when I would've taken that opportunity.
Random other note: cool that you play the banjo! I've recently begun teaching myself the fiddle.
My response to this has turned into something the size of the Lord of the Rings, so I'll blog it instead of clogging this page.
I need to get back to practicing the banjo. Perhaps one day we can hold a jam. The fiddle is awesome; I recommend the works of Darol Anger, and if you're near the Bay Area watch out for his concerts. Get on the Freight and Salvage mailing list if they have one. (I miss that place, although they have plenty of equivalents in Massachusetts.)
If I lived in the Valley and had an opportunity to hang out at YC dinners in exchange for a bit of free work, there was probably a time in my life when I would've taken that opportunity.
Random other note: cool that you play the banjo! I've recently begun teaching myself the fiddle.