Colletonguy,
Take a look at the 'fantasy' stories here and then ask yourself the same question that you're asking here on this forum. There are many guys that are poz that just want to get off, and have no regard for their partners. There are even more that don't know they are poz and love BB sex, just like we all do. Then there are those that tested Neg yesterday and actually are poz cause the test is only good from the time you actually had your blood drawn and the results normally come back in ten days to two weeks(unless you get a rapid test, which is not always reliable) which means if you have BB's since the draw, you could have been exposed!
The only way to totally protect yourself is to masturbate. The next best way is to not have BB sex with anyone, after that, all bets are off. I don't think that most of the guys online that are poz, would stealth you but you need to examine what it is you want and what risks you are willing to take. HIV is not what it was years ago but its still a pain to deal with and there are those few that meds will not work for. Eyes Wide Open!