alt Hacker NewsWell, you could have these "sleeper weights" only act on a specific day, rather than "$day + N", then people would have to prod every single future date to see if it could be malicious on that specific day, seems like a hassle. But I guess would be the only way really to detect it?
If it's only the day (and not time of day), then securing the next ten years would only take around ~3650 trials. Doesn't seem too bad.
(And the can't make it too precise, if they want their attack to work even if you don't use the tool at exactly the right microsecond.)