So failing on flatness or thickness demonstrates an astonishing lack of attention to detail / professionalism. . .
Unless it passed when he measured it himself, but somehow the sponge expanded (further) between his pre warm up self test and the post game test😪
a lot of players fall on thickness
now and then you will see a voc failure, but it is most thickness
I am not surprised if many of those that failed does not test it themselves.
How I came to know of the infraction list?
I once received a phone call from one of the pro team head coaches, who also serves on the Chinese Taipei national body and he asked me to help translate some documents sent from ITTF to him, which had a lot of TPE players on the infraction list for thickness lol.
Afterwards, I didn't see any more TPE players getting on. As of right now, still one player that hasn't "expired" yet.
So I know that from TPE side, they being a lot more careful about it.
flatness would normally be sanding of the blade.
that will be easy to spot if you remove the rubber.