Designs, thats absolutely true, the truck-driver and mailman elders usually dont have the training for this kind of stuff.
Anyway, though there have been lots of horrible cases where young girls have been humiliated with all kind of intimate questions by some (pervert) elders, not all the elders are like that. In fact, I remember one JC session of a young girl. The chairman asked her like this: "so tell us what happened" and then he emphasized: "there is no need to go into any details". Then she said something like "we did the whole thing". And then this elder asked if they had had sex only on one occasion or several times and she answered that. And that was it, no more questions about the actual act.
After that the JC just wanted to see if she understood that it was wrong what she had done (she had confessed herself) and she promised not to do it again. Private reproof and that was it.
The next meeting this girl looked like a different person, she was all smiling and happy so apparently she actually got some relief from this whole procedure. I think it was handled quite okay in this case.
So it really depends on what kind of men there happen to be in the committee.