That's probably closest to my view. If I run across a used one for a reasonable price, I would probably grab it. So if I installed it myself and did not do the "swinging", at what point would that be detected and become an issue? At sale? During an accident investigation? Asking hypothetically, of course.
Personally, I noted my "old" cracked and dry (but passed lord knows how many annual inspections) wet compass was made in 1981. Since my 7KCAB is a 1967, the compass was obviously replaced at some point after during or after 1981. I never found a log entry for it. I also never found any entries indicating it had ever been swung, even after the new ACA wings and rebuild in 2007.
I suspect it's something that is just not seriously enforced. The aircraft logs can be inspected during a ramp check if you (are unwise enough to) have them aboard, but they are not required to be in the plane and unless you have obvious non AN grade hardware or other non aircraft items installed, they are not going to ask you to produce them for an inspection. Practically speaking, it is really an issue between you, your A&P, and the AP/IA that does your annual if he or she is different than your A&P.
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Hypothetically....
What's in a particular aircraft's log(s) now? Any mention of the compass? If not, who is to say it hasn't always had a vertical card compass, or that it was installed decades ago in a prior aircraft log, or was missed in a log entry for a comprehensive rebuild?
Someone would have to go to a lot of effort to look for and not find a log entry for a compass installation. Unless an improperly installed and improperly swung compass is a direct cause, or contributing cause of an accident, I doubt anyone would bother looking.
In terms of discovery at some future sale, if you bought an aircraft with a vertical card compass already in it, would you even bother to look for the log entry? I suspect most buyers would not.