[Cthulhu_]

Another perspective is that you're a starving startup and grab a free logo to get started; if you ever get successful, you won't have forgotten that one logo and its artist that started you off back in the beginning, and then pay them for their contribution.

[antirez]

Trust me, people forget everything.

[cannonedhamster]

People forget everything, especially when there's a financial or emotional incentive to do so. This transcends any one field. It's a human trait. :( I've worked very hard personally because I recognized this to never forget the people who help me along the way.