I believe this post has too many different topics co-mingled in the dialog - - and other readers of this in the future will be confused.
In regard to: "the FE design must avoid having the same table open in edit mode, at the same time".
the FE design should not allow the user (same user, same PC) to have 1 table in edit mode multiple times simultaneously. so this doesn't affect multi users working separately in their own FE and it doesn't affect reports since they don't put a table into edit mode. so it is really about data entry forms. or it is about direct entry into tables/queries (that shouldn't be happening anyways typically). One should update the design so that only one form/object can be opened at a time.
the BE will lock up when it has table/record confusion....the scenario just described is a candidate to cause it - - - the other is if the key field is left blank and not immediately provided in new records....
older editions of Access were a lot more forgiving of this than seems the most current edition.