Maybe, but when people working in sensitive positions post their entire history, clearances, and build their own network and all you need to do is pay a nominal fee to become a LinkedIn "Pro" to get access, it makes fishing for the right targets quite a bit easier than classifieds.

Recruiting agents abroad is one thing - I'd think this would also be useful / more useful for social engineering attacks and other deeper attacks on sensitive networks. "Hey I was with you at university - want to grab coffee? Friend me!" > Now has access to the entire network of cleared professionals working at [place X]