Not too much to worry about with brett anyways. Brett is yeast and should be just as easy to get rid of as any other yeast strain. I think the fear of cross contamination with it is just hearsay and regurgitation. Either way, Trois is always invited to any party I'm having.
I agree the fears are overblown, and at the same time, Brett is extremely distinctive in both flavor and attenuation so if there is a little that makes it into a clean batch over time it will become an obvious infection, versus say, an English ale that you made that gets infected with tiny bit of left over US-05.