aaaaaaaaaaaaa left some good feedback, tether is an example of a big market with 0 collateral factor, which means we’d never be able to pause borrows (in case of emergency) w/o deprecating the whole market, which makes a lot of sense. so to deprecate markets, they suggested requiring 100% reserve factor.
implemented here Enable liquidations for all accounts in deprecated markets by maxwolff · Pull Request #123 · compound-finance/compound-protocol · GitHub