I've seen at least three tickets over on GitHub where people are having issues installing Phabricator due to a rare? Mysql setting. Maybe it can be detected and warned upon.
https://github.com/phacility/phabricator/issues/689
https://github.com/phacility/phabricator/issues/727
https://github.com/phacility/phabricator/issues/505#issuecomment-44231362