girdle question for experts

[Stephan]

In a very long thread about steep/deep diamonds, John Pollard said that digging could be used:

to improve a verbal description of girdle thickness or clarity: For example, a very thick girdle may be dug out enough so that it will appear only ''slightly thick'' to the grader, or an inclusion could be dug-out in order to improve the clarity grade.

Should we, buyers, suspect that every diamond that has "slightly thick" in its girdle description (for example ''medium - slightly thick'') might have a dug out girdle?
I know that GIA penalizes digging, but not if it''s very light, and that''s the problem: on a very steep crown, even light digging could have a very bad effect.
Thank you for your answers!