The whole spy system is structured for the sole purpose of techs being stolen to keep competition close. If you are in the lead (which is often the case on every difficulty other than Deity), then the system is working against you. I don't think it is much to worry about though; it keeps slow civs from falling even further behind.
Works the same way in real life. As much as military/corporations love to try and keep innovations to themselves (either in secret or attempts at copy-right) the fact is knowledge and equipment gets disseminated.
Works the same way in real life. As much as military/corporations love to try and keep innovations to themselves (either in secret or attempts at copy-right) the fact is knowledge and equipment gets disseminated.