Yeah I know, personally I prefer to use paper, way safer. I plan to just do the full TCP request by hand using the ethernet wire, morse-code-like, next./s

Sure increasing the functionalities increase the risk, it doesn't means the risk isn't worth it or isn't mitigable. Worst case, he fake your back button.. it's not that bad seriously. Google will probably try back buttons and different similar situation now on their engine and deal with theses cases one by one.