Bonnets, at least close fitting ones with deep brims (my preferred variety), also stay on the head significantly better than wide-brimmed hats, whether of the modern or period variety. Sunbonnets of soft cloth also have the advantage of folding up real small and then returning to their intended shape afterwards. I know the legends tell of foldable straw hats for modern people, but I've never seen one in the wild.
Now, I am a hat wearer in my everyday life. I dislike sunglasses because they pinch my temples, or they bump my eyelashes, or they are irredeemably ugly, or some combination of the three. But I also hate having the sun in my eyes and then having a squint-fest. Eventually squinting gives me a headache. The obvious solution? Bonnets! All the good qualities outlined above speak loudly in favor of bonnets. And, what do you know, I've already got a stash of them!

"So whats the catch?" you say. "There's always a catch." You know me and my black humor too well, my dear.
But you're right: there is one leeeeeetle problem.
Other people.
Now it's worth noting here that I dress pretty weird, in real life. There's a long origin story, but the end result is, I usually wear long skirts, tons of jewelry, regularly borrow articles out of my historical wardrobe, and generally stand out from the crowd. All this to say, I'm used to people looking at me. I'm even used to strangers asking me "What's the occasion?" as they walk by with a dog.
I also get more vocal attention. One particularly bad day I was walking home from work. At one end of the block a random guy asked me what play I was in. One minute later, at the other end of the block, a carful of pre-teen girls screamed "AMISH!!" out the window at me. I made eye contact with the car's driver. I hope those kids got an earful.
I've always found that my strange manner of dress elicits unusual responses from people, but something about the addition of the bonnet overloads people's ability to censor themselves. And of course, all of this is from the days before "Handmaid's Tale" came into our lives. This summer I've only just started to get the bonnet out (because a girl can only stand so much attention at a time, har), but I wonder if people's automatic reaction to the sight will be changed by this new infringement of bonnets into America's popular consciousness. If, and How.
Perhaps sometime I'll make a whole post about my unusual fashion choices. The obnoxious questions people ask often make me more determined to keep "being myself" - the more people are exposed to random difference, the less likely they will be to be randomly rude to other people who look different.
Well, it sounds plausible, anyway.