None of us knew that this would happen so there could be no pre-warning.
Dacon as the owner of the server should have known that Minecraft has ability to update the game and EULA though. Minevast is considered an online vendor and any type of vendor or business- especially for an online game needs to have a "Terms and Conditions" to make its patrons aware ranks (or anything bought in store) are affected by the EULA. I know nobody had any clue that the EULA would tighten up to this extent but its still important as a business to evaluate any possible risks before selling anything.