Status: OUT
Visitor's dual class hierarchy enables computation across structurally unrelated elements — but this structural independence is safely applicable only while visitor methods do not force element classes to expose internal state through their public interface, which would trade inter-element flexibility for intra-element encapsulation violation.
Structural independence benefit is gated on elements not being forced to expose internals
Depends on (SL): gof-visitor-two-class-hierarchies, gof-visitor-no-common-parent-required
Unless: gof-visitor-breaks-encapsulation