RefitTrim (except for special cases) changes the shape of the surface, not just the edge which was originally trimmed. RefitTrim may also change the shape of other edeges. Example below. (Example has been updated from original post)
The Help for RefitTrim should explicitly state that usually the shape of the surface will be altered, and other edges may be altered. The current help does not say or even imply directly anything about the surface shape being altered.
The current help for RefitTrim may lead a user to believe the command can rebuild the trimmed surface as an untrimmed surface with the same shape, with the only deviation from the input surface being along the trimmed edge. RefitTrim
Front is RefitTrim with no added knots. Rear is RefitTrim with 7 added knots.
RefitTrim Example 2.3dm (2.1 MB)