Quarantine is good. I have been glad I do it.
I have never had an issue with carpets who are defensive with humans being defensive toward each other. Not sure how this would work with species that are canibalistic.
Probing is proberbly the most accurate way of sexing an adult snake, get some good hands on instruction if you can before doing it yourself. Male carpets tend to have destingishable spurs, and some say you can tell by the length of the tail but I have found this unrelieable.