I see it needs to be defined better, my mistake...
Each company has 1, or more, human players who own it. No player is allowed to own more than 1 company. Players can still play using comapnies they do not own if that company is owned and they have the company owner's consent. Companies that are not owned will be opened up for new players to own or removed depending on how integral their existence is to the map. Previously owned companies that are now unowned, and so open for new owners, can be maintained by other players who own a company with significant vested interest in that company but cannot be claimed as owned by them. Company owners have the right to set their company password and request a password reset in case they get locked out of their company.
Creating of dummy unowned companies just to abuse the starting capital to help an owned company is not allowed and may result in the player's companies being deleted and for persistent offenders the player being IP banned from the server.
This means it would take at least 15 players for all companies to be owned. Players who own one company can partake in another company with that companies owner's consent. Companies that are ownerless and are too large/interconnected to be removed can be maintained by players who own companies that depend heavily on that companies operation, at least until a new owner is found who can choose to lock them out of what is now his company.
I did wonder about something similar to this after I posted the previous message. There are still possible problems with this approach. One is that it is possible in principle for a person wanting in effect to play multiple companies to use stooge players to create several companies which they never play, and then take over those companies and run them in multiple. Another, related problem is that there is no satisfactory definition of what it means to "own" a company. (It might be possible in principle one day to modify the code to allow the player who controls a company to allow secondary players limited access to a company, which can then be withdrawn, and which might even be limited in function, but that would take some time to code and the balance is currently a much higher priority; if you would like to do this, I should happily incorporate it. With such a feature, it would then be possible to have a meaningful definition of "own", although it might still be possible to use the stooge approach referred to above (indeed, this can be a problem with real life companies, too, which is why the law has a concept of a shadow director).
What I have done for the time being is to alter rule no. 1 to state,
Each player may play only one company at once, unless the player has the server administrator's explicit written permission to play more than one company.
Anyone who needs to take over a dormant company and act as caretaker can then just post in the server's thread on the forum to request permission. It should be fairly easy to spot abuse that way, and I do not anticipate it being an excessive workload.
A rule based system would be preferable, but it is difficult to define a rule which is not prone to abuse.
This is a bit too legally loose... For example in some countries digital piracy is not a crime so if some players were to post a link to such pirated content, possibly as part of "ordinary social pleasantries" for them, this technically is a big crime and one that could potentially even get you as the server owner (assuming EU or US server) punished for encouraging internet piracy. Hence it is important to define at least some legal region, usually where the server is located/registered.
The rules are not intended to create a contract (and they say so expressly). They are rather a guide to what I consider acceptable behaviour on the server. If people are doing things that are problematic, it is for me to decide what action to take to discourage or prevent people from doing those things. What would be the strict interpretation of the rules were the rules intended to be susceptible to a strict interpretation is thus not relevant to what I can properly be said to be encouraging or knowingly facilitating. Because they do not create a contract (and make clear that there is no contract between me and the users), they do not create any right enforceable against me to use the server in any way which may cause difficulty.