Mae Rheoliadau (Hysbysiadau Cosb) (Cymru) 2013 yn datgan bod hysbysiadau cosb yn cael eu rhoi ar gyfer methu â mynychu ysgol yn rheolaidd, hynny yw, absenoldeb 'anawdurdodedig' rheolaidd.
The Education (Penalty Notice) (Wales) Regulations 2013 state that penalty notices are issued for failing to regularly attend school, that is, regular ‘unauthorised’ absence.