Stephen (and others...):
There are two aspects of 'protecting' a profile's basic information:
1) Provide Sources. Both on the Sources tab and information in the About. Often folks complain about changes, but there is nothing to document what the correct values are. (Sidebar: many changes can be found in the Revisions tab and 'reverted' to an earlier value ... with the caveat that merges will not retain the 'history' of both profiles -- only one of them.)
2) Ask for the profiles to be protected with a Master Profile designation ... and be specific about which fields are well-documented and should be locked, if you deem it necessary. You can make such requests at this other 'sticky' Discussion: ("Curators: My profile is good enough to be a Master Profile!"... currently here: http://www.geni.com/discussions/142974)
It isn't necessarily to request each profile individually; one can provide a 'key link' and request (for example) all spouses, parents, and children. One should make sure that duplicates are merged and data conflicts are resolved.
Curators are interested in the correctness of the World Family Tree; everyone has a part in making that happen.