Originally posted by Egor Dobrynin:

The problem is that NAP insisted that it should be GL, that he hasn't known whether DTT was in hand of an AP and so on. On AP side were tons of tokens, and NAP had an empty hand and a great willing to get a playmat for a GD

At this point, I would investigate whether NAP allowed the GRV to occur specifically to get a harsher penalty for his opponent. You're either looking at a Serious Problem (JAR) or USC Cheating.

Especially under the circumstances, with the original error being GRV, or possibly L@EC, but not calling you until it's reached the point of being DEC. From the IPG:

A person breaks a rule defined by the tournament documents, lies to a tournament official, or notices an offense
committed in his or her (or a teammate's) match and does not call attention to it.
Additionally, the offense must meet the following criteria for it to be considered Cheating:
• The player must be attempting to gain advantage from his or her action.
• The player must be aware that he or she is doing something illegal.