unless those buying the seeds sign a contract which clearly states they assume all responsibility for what the seeds do to their environment
Well, I might not have the same perspective on "muh freedom", but you shouldn't be allowed to sign such a contract at all, because the scope obviously surpasses you. In an ideal world with an ideal justice system, such a contract should be void and both those who sold and those who used the seeds are responsible for the damage.
Sterile seeds have little to do with that, by the way, as they have been easy to produce and have been used for a long time already (sterility can be either desired or undesired depending on the crop, but usually it's just a side effect from hybridisation).
"The U.S. currently accounts for 47% of global credit and debit card fraud even though it generates only 27% of the total volume of purchases and cash". You really should not insist that the method used in much of the rest of the world, where fraud is 50% lower, is less secure. Because it really isn't.
Though I'm sure if you ever manage to switch, you will make sure to render your implementation completely flawed and useless, starting with idiotic "chip and signature" payments.
Or not. Maybe they'll just go to the library, or bookstore, or amazon.fr, or fnac.fr, or any other place where they can already find this.
The activity sensors probably senses whether the device user is active or not. Now does it mean physical activity, or actually using the device, I don't know.