When emerging sys-apps/slocate with an "slocate" group present on the system, I am instructed to do a groupmod -n. However, changing /etc/group is inadequate on a system using NIS, LDAP, etc. The ebuild should print a statement to this effect, although printing the groupmod command isn't a bad idea either (the majority of users probably do use /etc/group).
If you are using NIS/LDAP, you definitely know what to do. No need to confuse vast majority of users with irrelevant information.
