Just judge the kid like anyone else and move on. If it sounds like the audio has been tampered with (I donít see how it could have based on the restrictions from the program....), then call your region chair.
I have a kid whose dad is a sound engineer and she has a sound box set up in their entry way. Makes her sound like sheís in a giant concert hall. Itís insane and she doesnít even have a special microphone.
Nobodyís environment is the same, so the best you can do is judge like they were and not get uptight if the acoustics are different from kid to kid.
It's possible, with the right hardware. You can run the physical mic through any number of effects, then into an audio interface, then your computer just sees the interface as a microphone. Shady, but possible.
Also just as possible the recording was made on stage in the school's auditorium, or in a kid's tiled bathroom.
I haven't had this yet, but my understanding is that it's supposed to DQ the recording if it's altered in any way. It's part of why I'm still doing our recordings in our dry practice rooms instead of a room with more natural reverb...
Anyway, my procedure would be to contact the state about the issue and get a judgement call in conjunction with them. I believe though since it's specifically says not to do so, it would be a DQ. (DNA)
How do you prove it. It would simply be someoneís word against anotherís accusation. Itís like the honor band process, there are rules in place but ultimately all anyone has is your word that you submitted a recording that is in the spirit of the contest.