With all these steps in your process you have to take some things into consideration.
1. There is a lot of banned people so the program would be very strenuous on a server.
2. Who wuld monitor evidence? (With the ban / report rate you'd need thousands of people.(I don't think they'd work for free.)
There also is MCBans
http://www.mcbans.com
They are kinda good. Only server owners/admins can post or check here. But there could always be a server admin owner who is mad at someone.
Yeah, you're right with that. But since we're starting small me and 3 or 4 friends would do the monitoring and I would monitor the database itself on my own (including backups and stuff). The System wouldn't only be for that. i also hope that the knowledge of this program being installed would scare at least some of the possible criminals. And once we get bigger i would set up more than only one database. I already got some locations to make sure that my database here in germany wouldn't be the only one.
For future monitoring i already got a community that would do that for free. Not 24/7 of course but at least everyone would do a few hours a day, so that the day gets filled (even some from different time-zones, so we could really fit the full day)