Scott Weberpal
EF5
I think most reputable tour groups are up front about the possibility of periods of down times and most tourists also understand this uncertainty.
The company I work for had a tour starting right at the beginning of the 2006 ridge and we did everything we could to accomodate and make the tour as fun as possible without the prospect of storms for at least the first 7 days. He hired a world-renowned tornado scientists to speak to the group on the first day, spent a few days in the mountains going to various tourist area, and by the end of the tour finally had some decent weather. For those who could stay, we actually extended the tour by a day and those who could stay stayed, and those who had to catch a flight headed back to OKC.