As was recently discussed here on G2G, the Suggestion Report currently shows 626 profiles with Error 151, DNA test information being entered on a profile for a person who died before the testing was available.
Given that, and that many of the pre-testing profiles have contained erroneous DNA test information for years, I checked the "How to Get Started with DNA" Help page and pages that are linked to from there, including "Help:DNA Tests," "Help:DNA Features," "Help:Confirmed with DNA," "Help:DNA Confirmation," and "Help:DNA Comparison." In none of them is the Error 151 problem addressed.
While "Help:How to Get Started with DNA" asks "Have You Taken a DNA Test?" (emphasis mine) and uses the "Special:DNATests" link that directs the member to his or her own profile, there is no other specific direction indicating that DNA test information should be entered only on the profile of the person who was actually tested. I hadn't assumed this would not be widespread problem, but over 600 ancestral profiles in the suggestion list says otherwise.
I believe this needs to be clearly and explicitly stated on the Help page.
No assumptions can be made about an ancestor's genome from testing a living or recently deceased descendant, not even an mtDNA or yDNA haplogroup. NPEs occur at a not insignificant rate in most genealogies--among which I would include undocumented adoptions and name changes--normal meiotic and mitotic mutation means that siblings share only about 50% of their half-identical autosomal DNA, and even defining haplogroups may differ within just a generation or two (related to that, you can read how Blaine Bettinger and his mother are not an mtDNA match). Adding spurious test information to ancestral profiles renders the nightly propagation to profiles' "DNA Connections" panels inaccurate and impacts members' expectations of the provided data.
None of the direct-to-consumer DNA testing companies, past or present, has ever offered sequencing of exhumed remains. That level of both field and laboratory work requires highly specialized techniques and equipment, including clean-rooms and rigorous contaminant screening measures well beyond the capabilities of our common commercial labs. In fact, none of the major DTC testing companies offer even testing of cadaveric blood cards; some specialty labs do offer this, like GenAlysis and DNA Plus, however the types of tests conducted are not comparable to what we use for genealogy.
A small handful of WikiTree profiles do have valid DNA test information from the testing of remains--Richard III is one example--but there are very few of these and they are typically the result of institutional research projects published in academic journals.
I think explicit clarification on the DNA Project's Help pages would be proactive and help members understand that DNA testing information belongs only on the profile of the person who actually took the test.
* Edited to add: I neglected to note that we in fact have two different suggestion items reported for this issue:
Error 151: "DNA Test on person dead before the tests were available"; 626 current instances, with an additional 23 marked as temporarily hidden
Error 152: "DNA Test on person born 100 years before the tests were available"; 173 instances
For a total of 799 affected profiles; 822 including suggestions temporarily hidden.
* Edited to add: Having done a quick experiment adding DNA test information to a long-deceased ancestor, there is another place that a simple addition of text would be useful:

We could simply include: "The DNA test information must only be placed on the profile of the person who actually took the test. Do not enter your test information on any profile but your own."