@merlyn
There are ways around those issues. First of all there is no ambiguity about which pitch notation represents. The guitar is a transposing instrument. Music written for guitar sounds an octave lower than written. Transposing instruments are a bit nuts.
Believe it or not, I know this is how classical guitarists read. But I never play classical music: instead, I'm playing in a jazz ensemble, where I end up with an "obligato" part in maybe 1 / 10 songs, and even then I end up asking the musical director where he wants it played. Most of my job is to arrange the part, often on the fly, based on what other instruments are playing at the time, and usually given only chords and the melody line. So, if I'm supposed play a counter-melody when the trombones have the lead, I play up the neck: at that point, I have at least three choices about which string / fret to pick for playing the "middle C", and then need to decide on which fingerings are appropriate.