If using skinparam classAttributeIconSize 0, it is possible to use -, +, #, ~ for attribute visibility inside of classes instead of using the default PlantUML icons.
However, if I want to use the visibility for variables declared on associations, no icon shows up at all when using icon size 0 for + and -, and the icons also look weird for # and ~:
//www.plantuml.com/plantuml/uml/SoWkIImgAStDuIhEpimhI2nAp5L8paaiBdOiAIdAJ2ejIVLCpiyBpgnALJ3W0aieE8EbaJbEo1ndP8uBCiUL2w9LGLVN3gfHmKf1joono113nXaeemsKCSAGSG7AA0DbZ35aN84oTK0P4ow7rBmKe9y0
Would be nice to have it fixed, so you can also use +, -, # and ~ with icon size zero outside of classes 