I haven’t studied the Regulations closely this season (no need!) but IIRC the fine for crossing the infield was in substitution for the exclusions that caused so much adverse comment. Historically a referee fine was deducted from the riders wages, but when exchange money was done away with they became fines from the SCB akin to a parking ticket, and were loosely based on a number of points scored and the assumed pay rate for the rider and league.