Either case places the inventor without a patent in a bad position. At that time, it will be madness not to patent everything you can think of. While RMS is absolutely right about the degradation of our freedom as well as other harms of software patents, the current law and the positions and roles that it imposes on inventors and business cannot be ignored. A law has already been passed which grandfathers any user of a patented technology before it was patented. In other words, if you used the patent before it was patented, then the patent holder can't prevent you from using it.
Patents currently begin at the invention date.
If you used the patented idea before then, you would be the first inventor, and could invalidate the patent.