&gt; And what would be the channel for that feedback? Surely any such system would risk detection of the user, particularly for a non-technical user who may make a mistake in the (needed) security&#x2F;privacy software&#x2F;access needed for such a back channel?<p>How about using that nifty Tor browser they keep rebroadcasting to access a hidden service website to vote and issue requests? Hidden services cannot by definition be accessed without Tor and are thus more secure from prying eyes, even when used by non-technical users.<p>&gt; As for a more complex data transmission scheme, do all satellite receivers support it?<p>The satellite receivers just store the transport stream. The data is extracted by parsing the transport stream with a Windows program. You can implement whatever scheme you like with software.