We have runnng code that mailing lists are being created prior to official WG creation. I surely hope we aren't about to change that, and the above wording leaves me uncomfortable that we're maybe changing running code.
More than this... Some ADs require that there is an active mailing list, with substantive discussion, before agreeing to a BOF. It can be difficult to move these lists later.
Are we actively trying, at this point, to consolidate IETF mailing lists to the secretariat/ietf.org? If so, why? If not, then we don't necessarily have any say in how/when/if a mailing list gets created.