Just because it's open source doesn't mean it's open patent. Sure there's prior art which can prevent someone from creating a patent but if you actually want to

Just because it's open source doesn't mean it's open patent. Sure there's prior art which can prevent someone from creating a patent but if you actually want to guarantee that somebody doesn't patent your work, the path to do that is to file a patent yourself and open that patent up with patentleft (the patent analog for copyleft) or some other open patent. Yes filing patents can be expensive but for these companies it shouldn't be an issue and if they truly are a tiny org without the capabilities to file as a standard org, they can file under the small entity or micro entity fee schedules which are far cheaper.