If two (or more) coordinates are "close" to one another in the chosen CRS, they can end up occupying the same point after rounding. The errors which arise as a result are not indicative of the problem and so would be hard for a user to debug. Ideally implement a warning to the user if this is the case.
Check if there is any Shapely routine (or otherwise) to detect whether the points in a polygon will be "merged" as a result of a given rounding precision
If two (or more) coordinates are "close" to one another in the chosen CRS, they can end up occupying the same point after rounding. The errors which arise as a result are not indicative of the problem and so would be hard for a user to debug. Ideally implement a warning to the user if this is the case.