Events to open up avenue to new clients
I've shot and sold images from about 140+ events over the past 3 years. Mostly sporting events. Although this may not be your chosen channel/market to break back into...you are getting your images in front of thousands of people. I've had requests and generated a ton of other business from these events.
With that said...being the "official" photographer for the event typically qualifies you under their insurance and copyright terms. (Insurance...not always..but often...meaning you are part of the event just as their staff is). This legitimizes your presence at the event with your gear. And most, if not all, larger mass events, collegiate, high school sports etc. will either have a release on their application or ticket or on a sign posted at the entrance which in a nutshell states your picture may be taken and used. (Not trying to drum up a legal debate here).
With all that being said...
Every event I have shot I have shot it as the official photographer. As part of most of those deals...I give them a few promo shots or highlight reel cd. But...I receive permission and promotion in return. Alot of it. Onsite signage and announcements, website logo/link, inclusion in newsletters, etc.
One marketing tool and concept to both drive sales and cover your butt is to use an online service to market your image which has the necessary tools to increase sales and protect the subjects "right to privacy" option. I chose EventPictures.com. I can open or close access as much as I want via event passwords, unique event url's, etc. The site can be used for weddings, stock, fashion, sports, etc.
take care and good luck!