http://www.seatacguitarshow.com/events/

Never many ovations... but I have purchased 2 in the last 2 years from this event.
A little Positive Random Reinforcement... may be what keeps me coming back to this event

My suggested edit to wikipedia examples on the topic of Positive Random Reinforcement below:

https://en.wikipedia.org/wiki/Reinforcement
Reinforcement [edit]
Positive reinforcement occurs when a desirable event or stimulus is presented as a consequence of a behavior and the behavior increases.[12]:253 A positive reinforcer is a stimulus event for which the animal will work in order to acquire it. Verbal and Physical reward is very useful positive reinforcement[13]

Example: Whenever a rat presses a button, it gets a treat. If the rat starts pressing the button more often, the treat serves to positively reinforce this behavior.

Example: A father gives candy to his daughter when she picks up her toys. If the frequency of picking up the toys increases, the candy is a positive reinforcer (to reinforce the behavior of cleaning up).

Example: A company enacts a rewards program in which employees earn prizes dependent on the number of items sold. The prizes the employees receive are the positive reinforcement as they increase sales.

Example: Member of the OFC constantly goes to guitar shows hoping that there will be an Ovation that he does not have and occasionaly scores one.