I'm not judging nowadays (not since NWRBC this past fall), and won't be for a while. Nor was I a judge at the SERBC this past weekend. Nor have I talked to any of the judges from the weekend. On the other hand, I've been very involved in judging the past couple years, especially regarding interpretation of the USBC Rules & Regs. Okay. Disclaimer over.
"Smooth, round, bold" are part of the description for Tactile Balance for the espresso course.
Specifically, the Rules & Regs state: "The balance should be full bodied, round and smooth. Judges perception of viscosity will have an influence."
Now, to be clear, this is a separate scoring criteria from "Taste Balance," which has its own set of definitions and such.
That said, what you're questioning is whether or not it is appropriate for the USBC and WBC Rules and Regulations to promote "full bodied, round and smooth" as tactile and mouthfeel balance descriptors.
The opposite of "full bodied" is thin.
The opposite of "round" is sharp.
The opposite of "smooth" is rough.
Now anyone who knows me well within the context of the USBC and WBC knows that I'm not one to defend the wording of the Rules & Regs. Many sections are way too vague (on the Tech section, "General hygiene" is defined as... um... "hygiene"), and there's much to improve. Other sections perhaps pass judgement in an overly arbitrary or overly traditional way (color of crema is one). However, I'm struggling to dispute the judging criteria for "Tactile balance."
If the competitor's espresso was more thin-bodied, did they take the opportunity to describe it as such to the judges? Maybe they did, maybe they didn't. A good judge might make some allowances for an espresso viscosity that was described by the competitor as being a bit outside the definitions in the Rules.
So perhaps the definition in the rules is a bit too vague or terse, but I'd find it hard to dispute the content there.
Anyway, does that address your issue at all, Benjamin? I'd be interested to hear your response.