Hi!

My idea is when user with role e.g. "trusted" will add relationship e.g. "I am sure about this person" with someone, then the added user will give new role e.g. "trusted" too.

It depends on real live - when someone - "trusted" tell you about that someone e.g. John, is his good friend, you will start thinking about John that he is trusted person too.

My idea is that buddylist will be used to network trusted persons and when you will be want to get role "trusted", you will have to find someone who knows you and he will add you into his trusted friends.
(Usable e.g. for autostop(free place in car/hitchhiking) - you will be have to option choose if you want to show all nodes or nodes from trusted persons only) what can be very important e.g. for women

My opinion is that buddylist module is really great for something like this because all of this is about relatuinships between users/people.
(And users than don't need access for adding roles to someone, everything will be done adding someone into some category)

Other idea is when some person will loose role "trusted user" (someone remove this user from his trusted friends) all his friends can get mail/private messages about it...

I think that scope of this idea is large, but usability of worked something like this will be really huge.
IMHO it can be done (relative simply) by workflow-ng module http://drupal.org/project/workflow_ng
maybe it can be all in new module in buddylist - buddylist_roles

I found that module user_statistics http://drupal.org/project/user_stats has implemented something similar using workflow-ng
Cite from module desc.:
Another compelling reason for using this module is its integration with Workflow-ng. Using both modules, roles can be added/removed from a user according to their statistics. For example: a member could be promoted from 'Member' to 'Member Level 2' when they reach 10 posts and have been a member for 30 days. Roles can allow access to extra areas of a site, add user badges, or give users extra functionality.

thanks for your opinion
Igorik
http://www.somvprahe.sk