The example is meant to be a case of mere aggregation, as described in the GPL. The example is so short that it may not get the point across. Here is some more information.
http://www.gnu.org/licenses/gpl-faq.html#MereAggre gation says:
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"Mere aggregation of two programs means putting them side by side on the same CD-ROM or hard disk. We use this term in the case where they are separate programs, not parts of a single program. In this case, if one of the programs is covered by the GPL, it has no effect on the other program.
Combining two modules means connecting them together so that they form a single larger program. ... What constitutes combining two parts into one program? ... We believe that a proper criterion depends both on the mechanism of communication (exec, pipes, rpc, function calls within a shared address space, etc.) and the semantics of the communication (what kinds of information are interchanged).... pipes, sockets and command-line arguments are communication mechanisms normally used between two separate programs. So when they are used for communication, the modules normally are separate programs. But if the semantics of the communication are intimate enough, exchanging complex internal data structures, that too could be a basis to consider the two parts as combined into a larger program."
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The given examples are probably meant to be separate programs invoking each other by exec, and with no complex internal data structures passed, so a distribution that contained both would be a mere aggregation.
There is a continuum of possibilities for mere aggregation versus "parts of a single program". For cases close to the border, which side applies would have to be decided by negotiation or by a court.
