On March 5, Sequoia Capital issued a dire warning to its portfolio company CEOs, telling them to "question every assumption" about their businesses.

Flashback: At the time, the WHO wouldn't categorize COVID-19 as a pandemic for another two weeks. The NBA was still playing games in front of fans. Congress had just committed $8 billion to fight the virus, believing it to be a sufficient amount, and non-citizen travel from Europe into the U.S. was still allowed. Kids were still in school.

Nine months later, Sequoia's letter stands as prophetic, befitting a firm long viewed as venture capital's platinum standard. And, like with Sequoia's "RIP Good Times" warning from October 2008, this one deserves credit for waking entrepreneurs — and other VCs — to the mortal danger before it was too late.

• The goal, as Sequoia's Roelof Botha told me at the time, was to "sensitize" companies to compound risk, which is something people don't intuitively contemplate (particularly when it comes to public health).
• Sequoia didn't tell people their businesses were on the brink. Rather, it provided a brief playbook for how to lessen the odds they'd reach that point, advising founders to recalibrate cash assumptions and reconsider spending plans in areas like marketing and new hires.
• In short, the best way to keep the gravy train rolling was to give it a respite.

No, Sequoia didn't get everything right.

• The firm suggested it would take "perhaps several quarters before we can be confident that the virus has been contained." Clearly an underestimation.
• It also argued that Fed interest rate cuts "may prove a blunt tool in alleviating the economic ramifications of a global health crisis." That was true, but neglected to predict how monetary policy would help cleave the investment economy from the real economy, and how that dichotomy would keep fueling private and public equity deal-making.

The bottom line: We should all hope Sequoia never again feels compelled to pen another of these letters. But, if it does, we'd best pay attention.