Well of course there are going to be skeptics out there who will never trust anything the government tells them, but according to the Center For Disease Control (CDC):
Male Latex Condoms and Sexually Transmitted Diseases
latex condoms are effective at curbing sexually transmitted diseases (including HIV)...however nothing, short of complete abstinance from sexual intercourse, is 100% effective against STD transmission. I would think that being a swing type of person, one would almost be compelled to wear a condom (or ask there partner to wear one) as a safety precaution (and they're really not that bad) or to get tested for STDs and certified after each encounter.
Perhaps, maybe to go one step further:
Condom - Wikipedia, the free encyclopedia
This is an article assembled by our peers, that would in similar fashion represent what the CDC has to offer. This little bit of research took all of 5 minutes to find and "might not" replace all of the years of knowledge and experience that some of our peers in the swing lifestyle have to offer, but at least it's better than going along in blind denial. I also think that even presented with "the facts" some folks are still going to ride 'em bareback. A personal choice that will withstand any discussion on this topic.