Unfortunately laws and rules and even road signs are often written in ambiguous ways. My pet peeve is "a, except b, and c". Does the "and" goes with a or with b

Unfortunately laws and rules and even road signs are often written in ambiguous ways. My pet peeve is "a, except b, and c". Does the "and" goes with a or with b? Unambiguous language should use parentheses like maths do. Or avoid negatives ("not", "except", etc.).