Seeing teeth and brain spattered all over the road could be a good wake up call for others to wear their helmet. If you don't want to wear your seat belt or helmet be my guest. Insurance rates going up aren't significant enough to put a law on people wearing their gear/ seat belts.
Tyler, I'm sure if your girl ever hopped on your bike she would wear a helmet, and seeing that guys teeth on the road would take the, should I or shouldn't I wear my helmet today question out of the equation.
Seeing stuff like that is part of life. It gives people something to think about and be more safe in more aspects than just riding a bike.
Do what you want is how I feel about it.
I also don't get the blind spot thing with helmets. If you turn your head all the way like you're supposed to while backing up you will see everything that you need to see. You should also have mirrors on your bike so you can see what's directly behind you.
As far as merging, make the extra effort to turn your head another inch so you can see. I know it can be done because I do it daily. Helmets are designed so that you can see everything you need to while riding your bike. If your mirrors don't pick up something on the road behind you, you definitely have enough room to turn your head and pick up what your mirrors cant.