G2O About external modules.

[Julian]

The modules are one of the things that makes this g2 multiplayer better than the other ones currently available. If you realy want to remove it, you als have to remove the whole download functionality otherwise there are still many ways to load malicious code on the client system(e.g. proxy dlls or windows scripts).

If you realy want to remove the function, then make it optional. Let the launcher view an additional line which tells the useres if the server wants to execute "unsafe" code on the client or not. The users will have to decide if they  want to trust the server owner or not.

As Silvio already said, you should not worry about the bad things other people can do with you programm. Just add a paragraph to the terms of use which states, that you are not responsible for any abuse of your software.
This isn't solution. There is already a module, which allow you to open cdrom. G2O need admin rights, so loaded module can do everything.
I don't know how should I check if code is unsafe, so probably the best idea is make authorized modules.

Any others proposition?

You can not check if code is save. But you can say that any server that uses modules(clientside) IS unsafe. But that would only be a warning for the players which tells them that they need to find out theirselfes if they can trust this server.