Never underestimate the creativity of the American teenager (or willfully gullible coach).
As these devices clearly pose the same injury threat as the "bicep band", might these devices rationally be considered a type of knee brace (protective pad support device) and therefore be subject to NFHS 1-5-1-d2 and/or e, by requiring the device to be covered by the players pants? (Which would genuinely reduce the both injury threat, as well as the "adornment" appeal).