One basic and important difference in the two cases is that a zoo is not the same as a USFWS Plant Rescue Center. The latter are part of an official and fairly high profile USFWS program.
Just to clarify (not to you, Spaff, but generally), the statement
"If a given zoo receives illegally imported and/or confiscated CITES-listed specimens, then offspring from those specimens would not be legal to distribute within that country and could not be legally exported to other countries."
is claimed by a trustworthy source to come directly from USFWS. I read it as a statement of policy, but not as one that was subject to no exceptions whatsoever.
As I understand the
P. vietnamense case, an official exception was made for that species by USFWS. According to the
US Botanic Garden,
"In an effort to cool the demand for wild-collected specimens from decimated native populations of
Paphiopedilum vietnamense, the U.S. Botanic Garden has collaborated with a commercial orchid grower and the U.S. Fish and Wildlife Service to bring this orchid into legal cultivation."
As for
P. kovachii, Peru routinely issues CITES export permits since 2009. That species was described in 2002, and in 2004 Kovach and Selby were found guilty of trafficking it.
In 2007,
the AOS published this:
"There is a reason we made the hybrids we did — the five plants collected that day of our adventure are still considered the property of the Peruvian government. The plants are not allowed to be sold or to leave Peru, including artificially propagated divisions. All of the breeding must be approved by the Peruvian government and the only hybrids we could make were created with plants presently growing in Peru from Manrique’s personal collection of phragmipediums, so we were limited to what was available. It was also illegal to take pollen out of the country, because it would require CITES permits, which the government would not approve."
That strongly implies that as of 2007 no legal specimens existed outside of Peru, and in 2009 legal ones became available. It looks like there's not really room in the timeline for a permitted USFWS release of confiscated plants.
Since Tom Mirenda takes as his example the
vietnamense case in a
2007 paper (well worth a read for the overlap with herp concerns) but says nothing about
kovachii, I presume not only that the latter species isn't relevant to this discussion and that the former is an exceptional case. I don't know that I'd call such a distinct and isolated case a 'precedent'.