Follow up/continuation to #1003 as suggested/discussed in #1003 (comment) . Extracting here:

For that latter case (e.g. task-rest_bold.json and acq-tricky_bold.json) we could have removed this requirement ("subsequent ... is a strict superset ...") and require that for such cases of unclear ordering, order is arbitrary but metadata files MUST NOT have identical metadata fields overloaded (thus order would not matter).

        if multiple applicable files have the same number of entities,
        they could be ordered arbitrarily among themselves and they MUST NOT
        contain overlapping metadata.

It would be up for validator to ensure adherence to such a principle. This would "relax" inheritance principle further and allow for arbitrary combinatorics if so desired for some studies, e.g. mix in of _task-rest_bold.json and ses-pilot_bold.json, _space-X and _desc-Y in bids-standard/bids-bep016#32 etc.