The Webel Best Practice modelling tips and policies for SysML1.x and UML in many cases go beyond their semantics (to the extent they are defined at all) to introduce additional practices that leverage modelling paradigms and idioms for graphical model-based systems engineering and for managing graphing modelling of software systems.
UML does not define hard semantics, and was only originally intended for software engineering. The UML specification test does not apply directly or completely to systems engineering with SysML.
SysMLv1.x in many places does not have hard semantics, the OMG SysML1.x working groups have however at least tried to tighten the execution semantics.
SysMLv2 was conceived from the get-go to have tighter semantics.
Modellers are free to introduce their own semantics and indicate policies by applying custom stereotypes to elements. Take for example this tip:
Dr Darren explains:By rights I "should" be introducing an additional custom Stereotype extension and keyword for Dependency to indicate where this policy has been applied, but I am now using this policy so often that I am lazily (conveniently) using it as a default policy whenever using Dependency in systems engineering and only applying a custom stereotype extension where this default policy is NOT used.