Spam Guard

It was an easy walk to Gwen’s compartment: downstairs to seven-tenths gravity, fifty meters «forward» to her number—I rang.
Her door answered, «This is the recorded voice of Gwen Novak. I’ve gone to bed and am, I hope, happily asleep. If your visit is truly an emergency, deposit one hundred crowns via your credit code. If I agree that waking me is justified, I will return your money. If I disagree—laugh, chortle, chuckle!—I’ll spend it on gin and keep you out anyhow. If your call is not an emergency; please record a message at the sound of my scream.»
This was followed by a high scream which ended abruptly as if a hapless wench bad been choked to death.
Was this an emergency? Was it a hundred-crown emergency?
«The Cat Who Walks Through Walls» by Robert A. Heinlein

I {am soon|currently am|was} on vacation, during which my work eMail will auto reply:

from the 2nd of August to the 7th of August, I’m on vacation.
va·ca·tion (noun) an extended period of leisure and recreation, especially one spent away from home or in traveling (Apple Dictionary)
I am using the Gwen Novak method (Heinlein, 1985) to prevent unnecessary interruptions: If you think the message is urgent enough to warrant an interruption, transfer 4.50€ to []. If I agree that it is justified, I will transfer it back. If I disagree, I’ll keep it and get something nice with it. If it is not an emergency, I’ll get back to you after the 7th.
Best regards
Daniel Wessel
Heinlein, R. A. (1985). The Cat Who Walks Through Walls. Ace Books.

vom 2. August bis zum 7. August bin ich im Urlaub.
Ur·laub (Substantiv, maskulin) einem Arbeitnehmer zustehende arbeits- bzw. dienstfreie Zeit, die der Erholung dient (Apple Dictionary)
Ich verwende die Gwen Novak Methode (Heinlein, 1985) um unnötige Störungen zu vermeiden: Wenn Sie denken, dass die Nachricht wichtig genug ist, um meinen Urlaub zu unterbrechen, dann überweisen Sie 4.50€ an []. Wenn ich der selben Meinung bin, dann überweise ich es zurück. Falls ich dem nicht zustimme, dann hole ich mir etwas nettes mit dem Geld. Falls es kein Notfall ist, dann melde ich mich nach dem 7. August.
Viele Grüße
Daniel Wessel
Heinlein, R. A. (1985). The Cat Who Walks Through Walls. Ace Books.

Using the Gwen Novak method (see quotation above), I wonder — perhaps this is a way to filter spam in general. Keep a whitelist but have anyone else have to send you money before even showing you their email. And yeah, that would mean a lot less social contact in general. But on the other hand, contacting people has become way to cheap. Putting a price tag on interrupting others — with the understanding you get it back if it was justified — would be a way to reduce the noise.

Just a thought.