That sounds like a reasonable approach. I suggest making it explicit with a standard license such as CC0. https://creativecommons.org/share-your-work/public-domain/cc...
> 503.03(a) Works-not originated by a human author.
> In order to be entitled to copyright registration, a work must be the product of human authorship. Works produced by mechanical processes or random selection without any contribution by a human author are not registrable.
without *any* contribution
I'm not a lawyer. If I were, that phrase would give me a toehold or restless sleep depending on which side of the pile of money I was on...ok, actually if I was on the "hands on the money side", I would just advise avoiding the risk because that's what lawyers are expected to do.
Or to put it another way, the argument that works created by the program are not copyrightable might tend to be more expensive than simply paying licensing fees in a business context.But again, I'm not a lawyer.
The only way the copyright could belong to the author of the program, is if the program contained copyrighted material that it copied directly into the output.
For example, if the program contained 1000 prewritten melodies, and randomly selected one and copied it into the output.
Again I am not a lawyer though it doesn't prevent me from thinking along the lines I have observed laywers thinking.