An isolated local collision is resolved by nudging the one colliding glyph; three or more consecutive colliding slots means the underlying spacing is too tight and must be widened globally instead

Displacing a single glyph a small horizontal amount is the correct fix for an ISOLATED collision. But when a RUN of consecutive note-slots all require displacement, individually nudging each one produces a visually uneven, 'stair-stepped' result — the correct fix is to increase the passage's overall horizontal spacing rather than keep displacing.

A dense passage full of accidentals and seconds gets EVERY note in a 6-note run individually displaced left/right rather than the whole run being given more room, producing a visibly zigzagging line of noteheads.

Ross, The Art of Music Engraving states this exact aesthetic principle explicitly; Gould, Behind Bars implicitly agrees via its preference for generous spacing over cramped passages with many small nudges.

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