There is risk. I know that this is a common discussion on the boards. I recommend you do a search on this topic. There are several threads here with links to the CDC rubrics that show the activity and the likelihood of infection based on the activity. You could also do a google search or just check out the CDC site.

Understand that EVERYTHING you do in this Hobby has risks. Can you get a STD from eating pussy? I suppose. French Kissing or receiving a BBBJ? Perhaps. But, if you enjoy in partaking in these activities, and they are important to you in order to enjoy your overall session, then you simply ignore the small risk and have fun. It doesn't cross your mind at all. You, on the other hand are bothered by the inherent risk of contracting an STD, so you don't wish to partake in certain activities. If you don't want to eat pussy, french kiss a lady or get a BBBJ, then dont. Your cash, your choice, your session. You should only do what's comfortable for you. The good providers will gear your session towards your preference.

The risk v. reward is no different in selecting a really attractive (in your eyes) but un-reviewed provider. It may be a great session or a horrible time or worse an LE trap. But if a hobbyist is drawn to a lady's picture and profile, they may ignore the risk and take the proverbial plunge. Their choice.

In terms of hobbyists and providers on TER admitting to contracting an STD, I for one, really don't care what a group of alias posters articulate. Obviously, it would be shocking if someone admitted to contracting an STD posting under their TER identity (as many of us are known in this community by our handle). Thus, any admissions to your query, posting as alias, I would personally ignore.