Toronto Elizabeth S Mills seminar expectations and questions

Today I travel to Toronto for a one day seminar on Saturday for an event I've been anticipating for over a year. The Ontario Chapter of the Association of Professional Genealogists, the event sponsors along with the Toronto Public Library, describe Elizabeth S Mills as "one of the foremost genealogical educators of our day" and promise "a full day of stimulation for your personal or professional genealogical pursuits."

I'm expecting to learn from her experience and find out her views on a couple of specific items:

1, Can any more specification be given to what is a "reasonably diligent search." In particular, and from a practical point of view, if you already have several good quality sources for a fact all of which are consistent, locating and gaining access to another source involves considerable cost and inconvenience, and the information in that source is likely of dubious quality, would obtaining that source to examine that fact go beyond being "reasonably diligent?" Does the ease and cost of obtaining the source have any bearing on what is a reasonably diligent search?

2. In 1998 Helen Leary wrote "Science and the law are in agreement: there is only one way to prove kinships beyond reasonable doubt — DNA testing. As a genealogical standard, that is hardly practical."  Now thirteen years later DNA has emerged as a practical tool. What knowledge about DNA as a source does a client of an accredited professional genealogist have a right to expect?