Step 2: Open source projects implement whatever they want. Preferably, they provide a framework that allows high extensibility, if the software provider didn't already.
Step 3: People download and install open source plugins that violate stupid patents. It's still a patent violation, but as long as the people providing it aren't profiting monetarily, the ability to recoup damages from lost profits or royalties is very hard.
There's some nuance there, and different ways it could (and should) be done to avoid most consequences, but not so long ago (maybe still?) people commonly combined codecs and software from different parties for ffmpeg, which to get around some issues with distribution refused to compile the source and provide a binary, because that would make them a target, but just the source didn't (to a greater or lesser degree).
Where there's a will there's a way, and if a company is going to obtain stupidly simple patents which they often claim is to keep other companies at bay, we can put that to the test. If they go after individuals for usage, pressure them.
If we're lucky, what we're seeing is an ebb and flow between open source and the companies that capitalize on it, and we're in the ebb. I'm hoping for the flow.