I would guess that she was using a trailer like a BOB that has a rear skewer mount. That type would be usable on a carbon frame - it wouldn't put any stress on the frame. I would not try to mount a rack to a Ruby. It just wasn't made to handle it. Even if the load stresses weren't too much for it, anything that could potentially rub and cause the carbon to become scored would ruin it.
I'm with everyone else. The bike isn't really made for touring. By the time you'd outfit yourself with a good trailer, you probably have spent enough to get an entry level tourer... Touring bikes aren't just different because they can hold a rack either. They tend to have a longer wheel base for stability when heavily loaded, slightly different geometry for long haul comfort over snappy performance, and lower gearing so you can haul that load up hills.