A hairpin, slur, or tuplet must not be silently dropped across a system break — replace or split it

A hairpin that would need to cross a system break should either be replaced with the text convention ("cresc."/"dim." plus continuation dashes) or, if drawn as a wedge, both system-line halves must be drawn (the wedge stops at the right margin of the first system and resumes at the left margin of the next).

A crescendo authored from a note near the end of one system to a note on the next system disappears entirely from the rendered score with no error, warning, or visual trace.

Ross, The Art of Music Engraving, ch. Dynamic Markings, and Read, Music Notation, both direct that a hairpin spanning a system break is replaced by word + dashes rather than left dangling or silently omitted; Gould, Behind Bars, similarly favors text-based extension for long spans.

This rule needs the notated content and the rendered result together — the score says what should happen, the page says whether it did.