[Munch]

Honestly a cop is not going to know even if you show it to him, unless he is a biker. The chances of getting a fine are very minute as most inspections will be the only times you would get “caught” and even then I am unsure it would matter unless you have a tail pipe emission test. In NC motorcycles are still a safety equipment inspection anyway.
The Motor vehicle inspectors that control the stations are the only ones that would have authority to call you out on it.
Personally….. as minute a risk that it is…. not worth the effort, but there again the 900 is “loud” enough with open throttle and tame enough to talk over at idle.
I know riders that have done this and in reality there is no real high threat of fines, just wanted to point out that there is the risk out there.
Also some do not stop at just the three hole mod… the keep going till they take the full baffle out to “straight pipe” or “shotgun” it. In which case you will be eliminating the Cat.