In editathons and similar events we noticed that especially new people are put off when they add a statement and it triggers a constraint violation that really is merely a suggestion to add another statement.
We should introduce a new suggestion level next to mandatory and normal in order to be able to distinguish the really crucial ones from the ones that are merely used to suggest additional edits that would be nice to make.
"native language" has a constraint that says it also requires a statement for "languages spoken, written or signed". This is a mere suggestion to expand the data, not a hard requirement. There are other similar cases.
GIVEN a property
WHEN defining a new constraint for the property
THEN the constraint can be given the level "suggestion"
AND violations of this constraint are marked with a non-scary indicator icon
* constraint definitions can be given a "suggestion" level
* Violations with the suggestion level have their own less scary/alarming indicator icon
* What should the icon look like for this new level?