So far, my experience with potty training lies with my own kids (2 boys and a girl) and they were all different processes. I agree though, that there are some certain signs that must be present. The child must be able to express verbally that they need to "go". Dryness at nap time or in the morning is good, but admittedly, not all kids have that even when they are okay to train for the daytime.
Parents don't seem to see that taking thier child to the toilet every 15 min, and having them go sometimes and sometimes not; means that they are training themselves not the child.
PS> I wouldn't do the naked bum thing either. Even with my own kids. Underwear, fine. I always bought those super thick waffle-weave cotton ones that are special for training. But a child also has to learn that they need to say "Gotta pee!!" with enough time to take pants and undies off.
In your case, I would say that she needs some more practice at home before continuing to have accidents on your floor. I understand the continuity factor, but perhaps this needs to wait until mom or dad is home for an extra long weekend or a week's vacation...