Look at it this way, no one will ever have a 100% complete geocoin collection. So if you miss one or two along the way, no big deal. I've missed a bunch of geocoins and in the big scheme of things, there are more important things to worry about.
As for it being a private sale, based on Groundspeak policy toward charities, it couldn't be advertised on the forums.
On the "what I got in the mail today" thread, I see people posting "I got a super secret coin in the mail and I can't tell anyone about it" all the time. I don't get ticked at them for having a new geocoin and not telling anyone about it.
And BTW, Happy New Year to everyone!