Well this is an interesting point. I personally believe that the Flarm's users should also sign and the reason is easy: if they are a monopolist they can always decide to charge, as an example, a fee for using their device. If you put (always as an example) 100 EURO per year they could make 2.5 million per year on license fee. Not bad for them, not so sure for the users.....

Apparently Alexander doesn't like democracy on this but we all definitely like the Internet. CISCO has the vast majority of the router but they do not own the IP protocol. This is just to make an analogy with a market a bit bigger ....