Comment by r2_pilot

It doesn't even narrow it down to groups of people who live together. Consider this situation: your female dog in heat goes and seeks a male dog whose owner robbed a bank. She brings that microbiome contact back to your clothes when she returns. There could be a considerable distance between the two dog owners. Better hope you aren't apprehended or even better "It's not a search we're just patting this cloth against your shirt" in a drag net setting.