This came up in other conversations, and I wanted to make a policy statement regarding anything we're using for the radio, although I think it applies in general.
It's common for people to post MIDI files on web sites. Sometimes they do it to display their own work, sometimes they offer them for others to use and modify in the spirit of sharing, and I'm sure there are a few other scenarios as well. However, regardless of how or why they're posted, and without consideration of whether or not the song itself is in the public domain, these MIDI files are the intellectual property of the authors. Copyright law applies.
Because people post MIDI files with different motivations, and offering different permissions to the downloader, there is no one size fits all answer to how this should be handled, but the basic rule of thumb is that if you're using someone else's MIDI file as a starting point for work that you produce with GPO (or any other tool), then it's not really 100% original work on your part, and you owe them.
What you owe them will vary, depending on how they posted it, and it's typically not a money thing, but a credit thing. At the very least, if you use someone else's work in your own, you should make sure that a) you have permission to do so from the original author and b) you give them credit in your work. And of course, if they've specified any other stipulations for downloading their files, these must be respected as well.
I've hung out here long enough to know that we don't have any problems with disreputable people in this community. Those who show up and stick around here are good human beings. The problem is that in the Internet age, when it's such a common and casual thing to download a file, we simply get caught up in what we're doing and forget - that's an honest mistake, and we all make 'em.
Apologies for posting what most of you already know, but since I'm running a radio station, I wanted to make sure everyone gave thought to the basis of anything they submit to me. If it started out with someone else's MIDI files, please make sure you have their permission to use it, and also make sure that you include them in the song notes, crediting their contribution to your piece. It's the cool thing to do, and it will also keep me from finding myself in an embarrassing position, particularly since I'm a strong advocate of intellectual property rights.
So, if you've got songs up for the radio, please add credits for anything you've used, and if you don't have explicit permission from them for a given piece, please let me know so that I can pull it from the playlist until you get the okay on it. I know everyone here is supportive of this kind of thing, and I appreciate you guys helping me make sure we do everything in the proper spirit. Never mind that my idea of good spirits has to do with 12 year old rum...