Among its disadvantages is that, under a common-law system, legal certainty is frequently an illusion; it often falls to the courts to give "official" meaning.
At the same time, the 'hierarchy' model does not readily fit a common-law system.
However, at least outside the USA, common-law systems are moving in the direction of that paradigm.
As a result, some members refuse to pay their income taxes, and some groups operate their own common-law legal system.
An analogy might be made to the issue of legal opinions from courts in common-law systems.
As early as the 15th century, it became the practice that litigants who felt they had been cheated by the common-law system would petition the King in person.
There are said to be three preconditions of a common-law system based upon judicial precedent:
Furthermore, even in common-law systems, the hearsay rule only applies to actual trials.
(Most of the examples come from England, although they could be generalized to other common-law systems.)
In our common-law system, earlier court decisions create precedents that shape later litigation.