Definitely. Paying such a small amount, especially in credit that can only be redeemed in a company store, is patronizing and gets you mentioned in a negative light on Hacker News. If you don't pay, you're just like one of the many companies that doesn't have a bounty program.

Edit: this reminds me of the "eBay goodies" offered to researcher Neal Poole in return for delaying disclosure of a vulnerability [https://nealpoole.com/blog/2013/03/bad-changes-to-ebays-resp...]. I would probably not have remembered that story if not for that "eBay goodies" line, just as I probably won't forget this story thanks to the screenshot of Yahoo-branded socks in the company store.

I seem to remember having read that when something is done for free it is handled by the brains "maintain reputation and make friends" system, while when money is involved it is handled by the "make a profit, don't be screwed" system. My google-fu is failing though.