I honk my horn whenever I pass someone texting on their phone.
Why do you want to frighten people that way?
I think it's stupid to walk and text. When you walk around in the street you should be paying attention to your surroundings.
Although it can be frustrating to see people doing something you think is stupid, you should probably mind your own business. Even if you don't like the behavior, they aren't bothering you shouldn't try to antagonize them.
Well I don't want to stop because I want them to learn their lessons quickly.  If they don't stop texting and walking, they could end up in the hospital.
When you honk at people like that you are actually getting distracted yourself. You should stay focused on the road so that you do not end up wrecking or something like that.