Rob Understandable, I can see the justification in terms of preserving accuracy.
Do you really feel that 1E-6 is delving into the limits of numerical precision? A 64-bit system should be able to handle floating point values down to 10^-308, correct? I can see the historical argument for a >1E-6 cutoff, but on a modern computer, I would think any number >>1E-12 is sufficiently resolved. However, whether our physical models are accurate enough at such dilute concentrations is a different question that I can certainly see an argument for :)
The one time I tried modifying the text portion of a case file (i.e. to update the default file path for an animation sequence) the Fluent GUI refused to open and I had to delete the case and start over, so that's why I mentioned the "breaking GUI features" piece.