Props do not earn, or lose points, unless they detract from a show. I don't care what circuit it is. And on the visual sheets, props, the presence of or utilization of, is not a scored element. I defy you to find such a mention, except as used by a performer (say an umbrella, or a moving prop).
Now, on the effect side, how it all comes together visually, props can make a difference. But in my experience, unless very well coordinated, more negative than positive (used as an obvious transition, impediment to drill moves, etc.).
IF you buy into the concept of field show as musical theater, the presence of props and stage elements makes perfect sense. Imagine your favorite Broadway musical minus the staging, costuming, lights, etc. Even the concert versions of Les Miserables, while musically stunning, could be considered "less" than the full stage production.
Yes, different styles of band are better suited to some circuits more than others. A military precision band, or an HSBU show band would suffer immensely in SCSBOA. And some of the powerhouses of WBA have suffered score shock at an SCSBOA event, and vice-versa.
I did not watch this show. I cannot comment on what I think "should" have happened. However, it is incumbent upon me, as a director, as well as a parent and spectator, to believe, truly believe, that the judges have done their best to get the order of bands correct. Do I always agree with every judge on their numbers, or even some of their comments? No, not always. But I choose to participate in that circuit because I value the system.
I'm sorry if you do not agree with Arcadia's finish. IMHO, it is a disservice to every member of the Arcadia family for anyone to fan the flames of "not right." Those students and staff have busted their butt to be the best they can. To place their accomplishments in conflict with a judge, or contest, or another band, does not represent their best interests. You are certainly entitled to your opinion. But to place "blame" for a result you do not agree with on something else other than Band A was better than Band B today, puts the fans of Arcadia in a bad light.
Finally, to besmirch Mark Stone as a judge because of his exceptional experience in WBA and success at BOA, that is uncalled for. Knowing Mark as I do, to even consider that he would outscore one band over another simply because they have props is completely off-base.