I think what we have here is a confusion between rights and remedies. Causby tells you what your rights are. But it doesn't say much about what remedies you're

I think what we have here is a confusion between rights and remedies. Causby tells you what your rights are. But it doesn't say much about what remedies you're permitted to employ in securing those rights (except getting 5th Amendment takings compensation, which is what was going on in the case). These are quite separate legal questions. Ordinarily (but not always), you're limited to using peaceful means to secure your rights. That would generally not include shooting stuff, though there may be exception. So where I think you're right is that we don't have a good rule that tells you whether you can shoot a robot that walks/flies/drives onto your property. This is definitely different from shooting a person, and one could imagine it being permissible in certain situations. And come to think of it, we probably do have questions about your rights to remove or destroy other people's stuff when it's left on your property without your permission. That might be indirectly informative. But I don't have the time or inclination to really look into it at the moment. :)