GPT without L1 judge
What Dan has suggested.
I think there are several possibilites:
1) There was no certified judge present, the TO is ignorant, does not know about the requirement and did not mention any judge in the event in WER. The event will be invalidated automatically and the winner will receive no byes.
2) There was no certified judge present, the TO is dishonest and tried to cheat the requirement. The TO knows a DCI of a certified judge from the past and did enter it in WER. Judges have no tool how to see their judging history so we need to forward the suspicion towards WPN/WotC and they will - hopefully - investigate, contact the judge who is enlisted and find out the truth. The event will be invalidated, the winner will receive no byes and the TO's WPN membership will be - hopefully but unlikely - cancelled.
3) There was a certified judge in the event and you merely do not have enough info (not probable).