Blink (Dr. Who episode) Did they do this?

Right now I'm doing post blizzard clean up and then I have to head off to an appointment that I was going to reschedule after finding out my grandmother was dying but then didn't reschedule when I found out she died so the planned visit today was impossible which means two things.  The first is that I don't have a lot of time the second is that I don't have a lot of deep insight to offer beyond the fact that watching The Living Daylights (link to me talking to the movie) can take some of the edge off after a loss.

But what I do have is a question (remember I recently saw "Blink" for the first time), and the question is, "Did they do this?" I'm guessing the answer is no.  They should have done it, it would have been a great idea for them to do it, depending on their relationship to various people who put out DVDs they may have had the ability to do it, but I don't think they did it.  But sometimes people do in fact do things that they should have done, so they may have done this.

What is "this"?

The message the Doctor sends to Sally Sparrow in Blink, spread across hidden extras in seventeen DVDs, the only seventeen DVDs Sally Sparrow owns, has no connection to the rest of the episode.  It could have been recorded well ahead of time, well before the actor* playing Sally was even cast.  And it could have been put as hidden extras on 17 DVDs with no apparent connection except that they're the kinds of DVDs that someone like Sally Sparrow, a person who only has 17 DVDs, would have in her collection.

This could have been done well before the episode was filmed.  I could have been the first thing that was recorded when Martha was cast as the new companion and filtered into the newly released DVDs, piece by piece, leading up to the first airing of the episode Blink.

And if it were done it would have been awesome.

That's the "this".

Did they do this?

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*I try not to use "actress" because it just means "Female actor" and since there's no corresponding word meaning "Male actor" it gives the impression that women can't act, or at least can't act well enough to be called actors without a special suffix separating them from all the normal actors (who happen to be male.)

Some words will never be recovered (I don't see "Princess" going away any time soon) but others have been already (you rarely hear about "poetesses") and some should be (goddess means "female god" so there should be no problem calling Aphrodite a god because by definition she is one.  One of the more scary Greek gods regardless of gender, rather unlike the Roman Venus where she was pretty much tamed.)

Also I don't avoid lesbian because first it's not an "ess" word and second every time someone uses that word it's sort of a mini-tribute to Sappho (who came out of a culture with an idea of sexuality so different from our own that she might not have understood the concept of lesbian, since sex with females and sex with males were not seen as all that different in the culture, the difference was who was in control - but why quibble?) and since we didn't manage to preserve her work beyond a handful of fragments into the modern era (in spite of her being considered one of the two greatest poets of all time and being elevated to the status of Muse upon death, the only mortal so elevated) the least we can do is preserve her effect upon our language.