Don’t you think that configuration options are too easy to define? In my safe_vault fork I have used a static compilation flag to allow local networks. This is harder to use but I think this is safer.
Few vaults won’t allow other vaults to connect to the global safe network bypassing the controls implemented to keep a stable network (like the resource proof and only one vault allowed per LAN). But I am afraid that one day, malicious and ignorant people launch a campaign on social medias like reddit criticizing the limitations imposed by Maidsafe developers and promising to solve a scalability problem by allowing more vaults per station if people set these options.
Does that ring a bell?
On bitcoin network few nodes are needed to impose drastic changes (miners and exchanges). On safe network, a real numerical majority of farmers is needed (51%, even more if consensus rules are tightened). This means that such campaign can succeed only if operations are easy to do for a typical user, like configuring a file.
As you said it yourself, local networks are for developers and recompiling a program is not a problem for them. But this is not the case for ordinary users. Most of them cannot do it and will be reluctant to download binaries from another place than official Maidsafe repository (or more simply, too lazy).
This is why I think that a static compilation flag is safer than options in a configuration file.