I sure do like the sound of decals on windows, even if simply to remove some of the repetition when using glass on a large scale.
The problem with removing the border was already addressed by @jesshyland though;
And if decals were optional, glass without the decals would still require some indication of glass - not just thin air.
That said, pigeons fly into my windows all the time - stupid birds. I’d love nothing more than to see a Spitter charge full tilt into a plain glass window.