It's probably close to impossible to disable real time viewing. That's because many game formats rely on it (team games, simultaneous turn games etc) working so it's going to be a lot of work to sometimes disable it and sometimes not.
Anyone who attempts to 'sit 24x7' need to get a life It's very easy to defeat this by simply increasing turn times to 3+ days. No one is going to sit watching their screen for 3 days straight hoping to glimpse a unit or two. Plus most players are playing more than 1 game at a time (I am playing 10+ right now) so it's impossible to have 10 games open and viewing them all on only 2 screens.
KGB