Possibly useful search term is keyed connectors, though a problem is always that economies of scale mean like devices (such as two actuators) will be cheaper to make and keep spare parts for if they have common keying.

Not an answer, since it looks like it was a keyed connector and got partly connected anyway: llis.nasa.gov/lesson/53 + llis.nasa.gov/lesson/386

@GremlinWranger SE is all about good and interesting answers; I think you could summarize those in a "partial answer" or "too long to be a comment" post, and I'm happy to adjust the wording of the question accordingly as well so that answers are posted that users will appreciate reading.

If it's not cables, it's sensors: npr.org/sections/thetwo-way/2013/07/10/200775748/… Note that these were "clearly marked"

@OrganicMarble when I was little my father called things going beyond labels (like the blocking pins) "idiot-proofing". I don't know if the term is still in use today.

Welcome to the world of one-off design. If they were building rockets in million quantity assembled by $5-a-day third world automotive assembly plant workers, you bet sockets would be keyed. But the concept is, "If elite EE's are assembling this, they won't make those mistakes". That is a fallacy. They can and do.

"Incompatible lengths" may not be sufficient. There was an incident (a few decades ago) where two fuel pipes on a jet engine, that had been designed that way, were connected the wrong way round by a maintenance engineer, with the aid of a hammer. He even filed a suggestion to the designers to make them easier to assemble, but not before one of the connectors came loose in flight and dumped most of the aircraft's fuel overboard. Human ingenuity is boundless. The design was then changed to make the pipes different diameters, but some guy probably keeps a collection of adapters in his toolbox...

For every attempt to fix this problem by keying a connector, there's an anecdote about somebody sending a connector to the machine shop to have an unexpected key removed. There's really no alternative to having proper quality assurance and adequately-motivated staff.

@MarkMorganLloyd indeed those are critical as the block quotes emphasize as well, but they, along with your comment, might suggest a false choice, that there's and either-or... or an alternative. Good (idiot-proof) engineering or good QA. If I have my gall bladder out I don't want to choose between good sterile practices or a proper regiment of antibiotics, I want both, if either is implemented poorly I'm gonna complain if I'm still alive. I think that the "clearly" and "of course" that I've flagged are trying to push this false choice.

In cases where failures can be catastrophic, engineers should go out of their way to make it as hard as possible to do wrong stuff.

@MarkMorganLloyd but your point about enthusiastic individuals going to surprising and horrifying lengths to "get the job done" is well taken, so I've inserted potentially twice in the full statement of the question. Thanks!

@alephzero ditto. Thanks for the specific example.

The title of this question does not match the stated question, do we want to know if this is good engineering or what examples are there? (Or both)

@DiegoSánchez yes you were right! Since there are already five answers posted I need to be careful not to significant changes that might conflict with them. I've found a way to better align the title of the post with the question proper at the end of the post. Thanks for pointing that out!

@ChrisH thanks for the edit, that looks great! ! I've cleaned up comments no longer needed.