Absolutely it will be a target of intense espionage, but I think building the machine itself is only part of the trouble. A big part of making the machine lik

Absolutely it will be a target of intense espionage, but I think building the machine itself is only part of the trouble. A big part of making the machine like that work reliably is having the right sort of work culture, otherwise errors and anomalies will get swept under the rug with disastrous results. I think this will be even more necessary with reusable rockets than with one-off disposable rockets, since with reusable rockets you have to constantly re-validate used hardware, not just brand new parts. The right sort of safety culture isn't as easy to steal as some CAD files. Even if you stole all the plans, it would be many years of hard work to get an organization into the right sort of shape to build and operate the machine. As for SpaceX being a private company and therefore unusually easy to infiltrate... no. All US defense contractors are private companies, SpaceX being a private company isn't anything special. A B-21 bomber isn't made in a government-run factory, it is made in a Northrop Grumman factory. Spy satellites, missile seeker heads, stealth jet RAM coatings, IFF and crypto systems... all of these things are made by companies contracted by the government. The FBI/etc counter-espionage specialists are well accustomed to this sort of work, SpaceX is nothing special in this regard.