I know of someone who actively maintains 8 ORCID registrations. Each registration is associated with a slightly different variation of her name (given names, given name initials, original family name [alone], original family name with hyphenated married name, given name with married name, initials with family name, nickname and original family name, etc. She publishes in the literature of two rather different disciplines, she uses her nickname when writing for conferences, she uses a different name pattern for letters and editorials.

She is certainly an outlier but I know of _many_ people with 3 or more ORCID numbers (see comments about this in earlier posts to this thread).

So far, ORCID identifiers are only available for living authors who have approved the ID assignment. The VIAF system assigns IDs to authors (living or dead) of any published book, thesis, or report with an ISBN (and for 'famous' authors of publications released in the very distant past). Authors of journal articles currently aren't assigned VIAFs. Alas, some authors (especially those with multiple name variations or pseudonyms) have been assigned multiple VIAFs.

ISNIs have problems similar to VIAFs.

As an indexer, this drives my crazy if I think about it. Thus, I think about it as seldom as possible.

I lost my faith in ORCID when, during a teleconference of an ORCID workgroup my concerns about ways to improve the system were answered with, "ORCID identifiers were never intended as a disambiguation aid to indexers of literature but as a means for authors with similar names to _optionally_ identify their own works from those of others." I've not given up all hope and I try to influence the organization to change. I'm less and less optimistic the more I try. It is clear that my comments are more tolerated than welcomed.