I do carry a copy of the TSA rules (but have never had to 'educate' a TSA employee on them), but I always take the machine out of its carry on case and put it in a bin to be X-rayed. Sometimes they wipe it, sometimes they don't.
One other bit of advice I would give to travelers is to carry an extension cord with you. I have found that the outlets in the hotels are usually either full or in an inconvenient location. If you travel to Europe/Far East, make sure your CPAP machine is dual rated (110/230V 50/60Hz) and carry the right wall plug adapter(s).