> if Wikipedia is to be believed, there are books out there issued with
ISBNs that aren't valid, so any strong enforcement using the check
digit may lead to the occasional issue.

I can personally vouch for the veracity of Wikipedia on this point.  In
a library of our size, I've see it at least a few dozen times over the
years.  Moreover, a look at OCLC's "020 $z"s could undoubtly reveal many
more.

Publishers will be, well, let's say, human enough to make mistakes! 

JJ


**Views expressed by the author do not necessarily represent those of
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Jane Jacobs
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Queens Borough Public Library
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