I probably have a record for serving on committees. In the country I served in, almost every young person gets involved in something sexual. The married ones too, at least the husbands. I remember getting instructions for the circuit assembly that we needed to interview a long-time elder in our circuit who had a long, happy marriage. We had to borrow another elder from another circuit, because all the 43 elders in our circuit had either been unfaithful in the past, or had been married too recently. And since there are so few elders in each congregation, the CO often has to serve on the committee. Or find qualified brothers to do it. Sounds strange now.
But yes, where I served, most JC's are formed for sexual sins. I tried to be fair, or what I thought was fair. I never disfellowshipped young couples. I did disfellowship older brothers or sisters who took advantage of inexperienced ones. It's hard to be on a JC and be a missionary, because the local brothers tend to defer to your opinion.
I did serve on one where a brother was accused of murder though. Very, very interesting.
I will say though, that each JC is so different. You never know what the other elders are going to say. Some use the Flock book a lot, some ask to pray several times. Some have their own ways of being chairman. I always hated the ones who asked the person, "How would you feel if we disfellowshipped you?"
You never know what to expect from your fellow elders. Some love details, some don't. Some follow the guidelines, some don't. It's crazy how I thought it was all Holy Spirit.
Once the Branch told me to be "very careful" about disfellowshipping a brother in my circuit for smoking. So I took that to mean not to disfellowship him. Turns out he had bought land and donated it to build a Kingdom Hall, and then built himself a house on the same property. Problem with the title deed. What a mess. They finally met with him, the branch sent out reps, and they worked out a compromise.
I heard they disfellowshipped him a year later.
BF