As said above, you can basically report for horn spamming if it goes on for much longer than a usual "beep".
It is an annoying sound to hear, but you can also turn them off. Again to rival this, sometimes I'd like to have them on, but not to that extent.
Another issue which could arise if you had it off, there's a visual bug that often happens where the horn icon is next to someone's name but the horn isn't on. They're also not even holding the button when this happens, I am unsure if someone has been reported by mistake for this, thinking it's on, but be careful if you do see people.
In short, reporting it is easier, and if it gets too noisy when in a traffic jam, just untick that box and it'll be nice and quiet again!