A checkout from SVN/CVS only contains the last version. Files that were deleted in an earlier version are only on the server. A clone of a DVCS contains all versions and all files that ever were in the repo (unless you use BFG or git-filter-branch, but people tend to forget that). So a clone can contain secrets that people are not aware of, such as accidentally committed and deleted files. An interested party could find stuff that you're not aware off by looking at HEAD.
> (not that you would allow checkouts on unencrypted laptops anyway)?
That's not my call to make, but I agree on that regard. Reality sadly different from what we both wish.