40A. Material. Pieces should be made of plastic, wood, or posibly a material similar in appearance.
40B. Size. The king’s height should be 3 3/8 to 4 1/2 inches. The cross should occupy no more than 20 percent of the total height of the king. The diameter of the king’s base should be 40 - 50 percent of the height. The other pieces should be proportional in height and form. All pieces should be well balanced for stability and comfortable moving.
40D. Color. Pieces should be the colors of naturally light and dark wood or approximations of these colors, such as simple white and black.
39A3. Non-USCF play. For non-tournament or non-USCF-rated play against opponents not used to popular tournament sets or boards, equipment differing somewhat from these standards is likely to be acceptable.
Do understand there is a problem with non-rated scholastic tournaments with non-standard equipment. Even if it was a rated tournament, it is up to one of the players to make a claim of the set not being standard equipment. In most case it is white that makes the claim, as black has the right to use whatever standard set they want, if the organizer does not provide standard equipment.
The director has very little power under rule 40, and rule 41: if both players agree to the non-standard equipment. As your son did not make a claim that the glass set was non-standard equipment for the first game: the director has no empowerment to force both players to play with non-standard equipment. During the second game, your son used his rights to make a claim that the glass set was non-standard. Have looked and been around the type of ‘glass set’ you are talking about, it is clear it does not meet the standards under rule 40A, rule 40B and rule 40D. The director did remove the set from the board, and set up the standard equipment.
If for example, WGM Anna Zatonskih (person I have meet 3 times and talked with) and WIM Jennifer Shahade came to my tournament, during the tournament they are paired against each other. If they want to play with a non-standard equipment, there is nothing as a director I can do to stop them. The Official Rules of Chess give me no right to force the players to use standard equipment. There is a rule on page 223 - 224 of this once sentence; “The director is the final arbiter of whether the equipment in question is standard.” The word to look for is arbiter, as the director cannot make the claim and also be the arbiter at the same time. The director and the spectators, as parents are the spectators in any tournament, have no claim on what is or is not standard equipment.
If one of the players makes a claim, as only the players on the board can make a claim: then the director will have the right to make a judgement, and the final judgement on standard equipment will be the director. The director was not in error if players use non-standard equipment, as only the director can make a judgement if one of the players at the board makes a claim.