This type of bait-and-switch tactic with local charities is at the heart of the lawsuit against Competitor. According to press reports at the time the suit was first filed, it's not that the law prof originally expected that she herself or other volunteers would be paid, but that she believed that her volunteering would help generate funds for a specific local charity. When she learned that her designated charity in fact had to PAY the Competitor Group upfront simply for the opportunity to be named as a designated charity recipient, she cried foul.
It's fitting that you mention Raleigh as an example, since the law prof initiating the lawsuits volunteered for St. Louis R-n-R twice as a bicycle escort. As a Raleigh-area resident, you are doubtless familiar with the exquisite poetic justice of this year's Raleigh R-n-R event: the Competitor Group got exactly what they paid for from the bicycle escorts.
http://www.wral.com/durham-runner-veers-off-marathon-course-wins-race/14588892/http://www.letsrun.com/forum/flat_read.php?thread=6446026