[1] "Low-risk, commercially available software" might introduce a vendor's solution for meeting a customer's need to buy technology that enables quick, relatively cheap authorization for people trying to use a credit card.
[1] The use of theme statements in proposals is based on a reading comprehension technique called an "advance organizer", developed by learning theorist David Ausubel.
[2] The advance organizer serves as the launch point for a deductive logic string, where the primary idea is introduced first, followed by supporting detail in descending order of importance.
Ausubel's research demonstrated the technique was particularly effective if the reader had little prior knowledge of the subject material.
Finally, in concert with Ausubel's findings, theme statements should not be used to introduce sections in a proposal customers already know well.