Co-authoring on M365 documents is a game changer, but not when an unknowing participant "frees" a document -all changes from all co-authoring participants are lost. At present, the free option is controlled at a user level in DI - so turning it off at that level affects every document in every project that the user interacts with.
A useful enhancement would be an Admin switch at the 365 project level to control the "free" option to that of the initiator of the co-authoring session.
Guest
In case this is not know
You can ask SP admin to unlock the Trash bin and recover any co-author document from that location, in case being free unintentionally