Of particular interest to cvs users are 
(a) notification by email to a list,
(b) user responsibility for meaningful comments,
(c) user responsibility for test-before-commit, 
(d) manual conflict resolution requirements

See the example of the cvs diff file between 
a checked-in version 1.2 in conflict with an
alternate check-in candidate derived from 
version 1.1 (predecessor of v. 1.2):
(User version moved to #filename;  merger
of two versions now in user's filename is NOT 
legal C/CC syntax until diffs resolved.)

THis is a second update to the same set of 
>>>conflicting updates<<<lines from /usr/proj3/case/95sbde/bde
where I checked out cvs.help for editing <<<more conflicts>>>
in parallel to the checkout in ~/95sbde/bde.
This update will be committed first;
the update in ~/95sbde/bde will be rejected.

This paragraph (tried to) demonstrate what happens 
when I check out  v. 1.1 twice and change the same or any
overlapping subset of lines in two places,
then attempt to check in both.  But it was too simple - 
cvs merged the updates by appending them serially 
to the end of the file. A new pair of revs (1.3 and 1.4)
is being tried now. This is being added as rev. 1.3;
Then, back in ~/95sbde/bde I'll try to add rev. 1.4.