I travel with my machine all the time, I am on 18-24 flights a month and I have never had a problem with taking my machine, this goes for domestic as well as international.
Some places do swab other do not, it is very "well what do I feel like doing" type of thing. At one airport I just went through and I had to go back out of the screened area. Five minutes later I went back through, same TSA staff and they swabbed the cpap. I had to ask, he told me they swab all cpaps, I pointed out that they don't and told him that HE did not swab mine 5 minutes a go. He got mad and started to get cranky, I just left.
TSA, an oxymoron.