I am not sure where you get the 2.5% transmission chance from. Getting gonorrhea in one part of your body doesn't mean it goes to other parts.
And most people don't test for or know if they have gonorrhea in the throat because it's asymptomatic. However, a working lady sees a lot of cocks, so it could happen easily.
I've gotten gonorrhea, it hurts like a bitch. Getting the uncurable kind would likely suck even more.
Moreover, getting any STI increases your chances of getting others -- including HIV.
It's best to be as safe as possible.