Extra privileges required

The problem is what to do when a program running as a normal user needs to have extra priviliges:

Users should be able to 'ping'
Requires ability to make and receive ICMP packets

Users' screen saver should be able to verify your password before letting you in
Requires read access to /etc/shadow

Users should be able to write to other user's terminals
Requires group 'tty'

Graphical terminals need to be able to write to /var/log/wtmp
Requires group 'utmp'