Hi Steve
The result color of rs.BooleanDifference is opposite than Boolean Difference in VBScript and Rhino like the attached picture.
Ciao Vittorio
import rhinoscriptsyntax as rs
obj1=rs.GetObject("obj to subtract from")
obj2=rs.GetObject("obj to subtract with")
aa=rs.BooleanDifference((obj1),(obj2),False)
rs.DeleteObject(obj1)
Ciao Vittorio