Re: The trial account restrictions.
If there are any possibilities for a single trial account to get 50 million NIC (with you not knowing where it came from) there is something wrong with your source code that may not be fixed by a set of limitations grown off some paraonia...
That is the "safe" part. Of course we can trace everything back when and if we find it, but it may already be too late - see insurance frauds. This is a sandbox where we actually expect the players to use the given tools in new and surprising ways that we never thought of. But a fragile economy is one of the things where we don't like surprises.