In the list of probable lies control questions, there are a number of questions that I'm concerned about showing a reaction to. 

Since being on probation, have you lied to your probation officer?
Since being on probation, have you lied to your therapist?
Since being on probation, have you lied to the group?
Do you still want to engage in those sexual behaviors that you know are wrong?
Do you still want to engage in those sexual behaviors that you know are illegal?
Do you think you would sexually re-offend ever if you knew you would not get caught?
Are you lying to me about the last time you touched your thingy while having a thought of a child? 
Do you still want to have sexual contact with girls under 18 years old?

All these questions seem like if you show a reaction to them, you're going to have some questions to answer. For instance in the polygraph that I failed, I was asked the first three question in this above list. He failed me on a different question, and then said I also had a bit of a reaction about lying to my PO and therapist. So does that mean they are relevant questions or what?

I may be a bit of a dummy, but what exactly does caveat used mean? 

Okay, that makes sense.

However, there's something else I'm wondering about on the same topic. One of the members of my therapy group failed his poly as well. Turns out he lied on three of his questions and was called out on it. But what raises red flags to me is that one of the questions he failed is listed on your thread as a control question. How can he fail a control question? 

I suppose it's possible they called him out on it and he admitted something. But I don't know if that is the case since he didn't say so to the group.