Clarification on rdf_reifies requirement for triple terms

Hi RDF-star WG,

exploring triple terms and reified triples more closely, I find that
both [RDF12-TURTLE] and [RDF12-CONCEPTS] assume that triple terms
are only ever used as the object in triples with the rdf:reifies
predicate.

Is this only a semantical requirement within the entailment regime
assumed by these documents?

Or is it a technical limitation? If so, how is it to be enforced?

What, in the eyes of the WG, would happen if I used a triple term as the
object of a triple with some arbitrary predicate?

Kind regards,
Nik

[RDF12-TURTLE] https://www.w3.org/TR/rdf12-turtle/
[RDF12-CONCEPTS] https://www.w3.org/TR/rdf12-concepts/