How do you flag misleading postings on Facebook and elsewhere about vaccination, Covid-19 and other issues? Currently these platforms add a little warning next to the posting. Evidence accumulated over many years has shown that such “contextual” warnings are mostly disregarded. What does work is “interstitial” warnings: something that interrupts the user, and forces them to make a choice to continue. This works for security issues on PCs and when browsing the Internet; it can work for postings on social media, too. This article <https://freedom-to-tinker.com/2021/07/26/warnings-that-work-combating-misinformation-without-deplatforming/> goes into more details.