I am a little confused about the setting for "Tech Stealing" in Game Options for a new game. The manual seems to state that by checking the box you are disabling the ability to steal Techs, rather than enabling it, which seems counterintuitive.

With the box checked, I have never stolen a tech via espionage, despite getting Advanced Espionage on all other races (and I have checked, they have many techs I do not possess). However, at the same time I have stolen techs via invasion.

So my question is : does checking the box allow or disable Tech stealing via Espionage, and does that have anything to do with tech stealing from invasions? On the chance that I do in fact have tech stealing enabled, is there a reason I have not ever stolen a tech through espionage? This is over the course of perhaps two-dozen different games...

Thank you for your time and input.