You make a good point, but to counter, can modern touchscreen phones be used without looking at them? Volume buttons and power off / on can be used without looking, but you can also use those without unlocking your phone.
For example, if you have an app open in a folder, you'll have to press the home button 3 times: once to exit the app, another to exit the folder, and a third to go home (unless the messages app is on the dock, then you can press twice to reach it).
I'd be worried about messaging the wrong person, and I also have fat fingers so that's no help :(