Yes, better to be uncouth, speaking with a piece of spinach pinched between the eye tooth and incisor, flapping about like some felt Jets pennant flag.
Seriously, what's the big deal about going to a lavatory and addressing the issue in private?
Oh, I don't think it's a big deal. I just think it's a little eccentric. But in the scenario you describe it is the least bad, most couth option. You're right, can't go around with spinach in your grill all day.
Maybe I'm too dainty, but I cannot release the doots whilst someone is brushing their teeth in my vicinity. there is just something so wrong about filling the air with rancid gas while some fastidious soul attempts to freshens up his mouth a few feet away. So, in that sense, I understand the OP's rage at the people that cause this situation.