There is no law in the land that compels seconders to supplement a proposer's motion, (though it is quite common for Standing Orders to require a seconder before discussion on a motion is progressed). Of course, by logic, a motion must be formally moved (presented) before it can be seconded, discussed and progressed. Presumably a main motivation of such a modification of standing orders is to prevent scenarios where the public can see motions moved but not seconded, and in order that people won't be able to see situations where the Council does not want to discuss a particular motion that is tabled.
So where a Council resolves to amend its Standing Orders to introduce a new rule compelling any Member requesting a particular motion be included as an Agenda item (including stand-alone motions without an accompanying report) to also name a seconder when submitting the Agenda item request (ie, such that without naming seconder in advance, a stand-alone motion will not be included on an Agenda and therefore cannot even be moved) does this not put the cart before the horse and create an illogical and unnatural barrier to democratic process? Is it right to require a would-be proposer of a motion to solicit potentially all other Councillor colleagues for a seconder even before Council has heard the reasons for the motion being presented and the proposer given an opportunity to move the motion at fist instance? Is it not a barrier to openness?