I devoted a good ten years of my life to obeying the articulation indications of the Urtext. I was such a stickler that I often insisted on playing from manuscript facsimiles whenever possible. When it was not possible to play from an Urtext edition I would use white-out to remove "interpretive" articulations from my modern editions of baroque music. I truly believed that the key to great flute and recorder playing was to have as little distance between the "horse's mouth" and mine. And I stuck by that belief dogmatically until the time came for me to stop hitting my figurative head against the figurative wall.
It took about two years for me to develop enough technique to muddle my way into a string quartet. I had three string player friends, a viola (purchased for $100 at a yard sale), a pulse, and I could read music. In my neck of the woods that, and the ability to make arrangements, was enough.
I distinctly remember my first string quartet rehearsal. Everybody took out their pencils and, after careful discussion they changed the articulations in the music. Where a composer wrote a long slur, it was deemed more legato to divide up the notes into two bows rather than keep them on one. Once my jaw finished dropping, I kept my mouth shut and changed the articulations the way my far more experienced colleagues told me to change them. I pretended that I understood, but it took me a good ten years of violin and viola playing experience before I even got a clue. I knew that I would have to make a clean break with my baroque flute and recorder-minded idea of the Urtext if I wanted to continue as a string player.
The idea of a passage being more legato when a slur is broken is tremendously liberating, especially now, since I understand the concept physically. A lot of 19th-century music written by pianists (Clara Schumann comes to mind) have phrase markings in their violin parts that look exactly like slurs, but they don't function like slurs. They function as pianistic phrase markings. I imagine that Clara Schumann, who knew very little about the physicality of playing the violin, trusted Joseph Joachim (the person she wrote her violin music for) to take care of the violinistic business of bowing. String players even need to change bowings in order to match the way that wind players make slurs. A stroke of the tongue on a wind instrument is a different animal (or a whole different zoo of animals) from the stroke of a bow on a string instrument, and these strokes only match successfully when the musicians are very sensitive to one another. Context usually comes into play.
Thanks to becoming a string player I have a whole new perspective on the Urtext. The Urtext is not an authoritarian document. The Urtext (and I'm talking about 17th and 18th-century music now) usually has the intended notes, the intended rhythms, articulations, and the composer's phrase markings. The composer leaves the interpretation of said notes, rhythms, articulations, and phrase markings to the musicians who are playing. Just because a composer didn't write a crescendo mark between the "P" of piano and the "F" of forte doesn't mean that all the notes that lead up to the forte are supposed to be played piano. A dot or a dash or a wedge is a composer's suggestion, and the interpretation of an accent mark has everything to do with its context. It is up to us to create a context where the music can live.