Of course, many times these opportunities are brought to your attention by your own customers, and many times they are good customers who support you as well. Sometimes this is not the case, and you get to judge how much you want to be 'seen' throughout your community as a benefactor by selecting or turning down these events.
I attended just such an event last evening and was once again reminded how really pointless these events can be for a small retailer such as myself. This is a well-attended event, with long lines at the food vendors' tables, so when people arrive at your table, it's a given that they will pile their plate with selections with very little regard for any behind them in line.
At my particular table, on a single toothpick, you'd see a pepper jack cheese skewered to a salsa and cilantro cheese, followed by a piece of salami wrapped blue cheese. You have to try to get a small explanation of each piece going on the toothpick in random fashion as these individuals are moving through your line. And yet, really, there is little hope that any individual flavor will stay with the taster as they cram a piece of bread, cracker or any other little nosh from someone else's table into their mouth.
I have had very little return on the investment of my 'donation' or my time at these events, but I continue to do them - WHY? As a small payback for the loyalty of my customers to my establishment, I suppose. These are their pet projects, and they do serve a purpose in the greater community in which we live through their service of housing for cats & dogs, or historical education for the community, or even music programs at local schools.
So, I will continue to agree to participate, or not; I will continue to spread the word - and I will continue to marvel at some of my fellow human beings 'table manners'!