So basically it sidesteps the type system issues in a similar way that an inconvenient car trip instead of taking a flight sidesteps the TSA issues? ;)
Adjacency matrices would make ownership clear and solve the single-writer/multiple-reader issue because nodes wouldn't directly reference each other, but it keeps the exact same relationship between nodes, so any memory leaks are still possible (e.g. not cleaning up dead code because it is cyclic and appears to have references). If I'm going to defeat the type system, it seems like raw pointers would be easier.