Never had an issue, never checked, no one said anything ever, at any race, at any track.
Rules per the race organization hand book though for bikes stated half throttle revving at a 45 degree angle from the muffler tip at like 4 feet away (clearly not the same). I did my own testing because I thought they'd check which they never did. Max couldn't be over 105db. My bike was 105db. Which means WOT on the straights I know I was pushing 130+. After every race I was asked "was that you? O man that sounds insane. We can pick your bike out of everyone around the track." Again no complaints, just other racers liking the unique sound.
And since I raced at Pittsburgh where pulling in says 95db max, I think they're full of **** on it.
