From a post to DAVIDWEBER.NET forums on 8/11/2011

The 'completeness' of Merlin's intelligence coverage

    There seems to be some question about why Paitryk Hainree was able to get so close to whoever his target may be (as he apparently does in the teaser snippet I posted), since he's being followed around by his own personal SNARC bug.

    First, I wish the readers would disabuse themselves of the belief that Merlin's technology is infallible. It isn't, and it's entirely possible for someone to "get away" from one of Owl's "personal bugs." For example, if the bug is planted on an article of clothing which the changes and leaves home, or if it is planted in his personal quarters to keep an eye on him and he isn't there, or any number of other possibilities. Normally the person being followed will be reacquired when he comes back home, there's time for the bug to be moved from one item of clothing to another, he drops in on one of his fellow conspirators who's also being watched, or whatever; that doesn't always happen, and Merlin and Owl do not have complete, total penetration to keep track unfailingly on every single individual of interest's every conversation, every piece of correspondence, etc.

    My point here is (without going into any additional details from the book) that I have never given Merlin and his friends 100% intelligence; there have always been gaps and there always will be gaps in their coverage. When they know that it's absolutely essential to have total coverage on a given individual — like, for example, Earl Thirsk, or Princess Irys and Prince Daivyn — then they'll go all out and probably dedicate an entire SNARC, and not simply individual bugs, to the task of keeping tabs on that individual or small group of individuals. Otherwise, even with Owl, there has to be a level at which they simply say "we cannot keep track of every grasshopper crawling around down in the weeds of our opposition."

    In short, once Paitryk Hainree avoided the initial dragnet when Koryn Gahrvai swept up the vast majority of the "resistance leaders" upon whom Merlin gave him targeting data, it was entirely possible for Hainree to "drop off the grid" with sufficient totality to make it impossible or, at the very least, extremely difficult for even Merlin's resources to find him again. The most probable way for them to have reestablished coverage on him would, of course, have been for him to become active in another organized "resistance movement" in Corisande. For some reason [tum-te-tum-te-tum] that would appear not to have happened in this case, however.