B2C events are prime candidates for event engagement on social media. Many smart phone users go to events LOOKING for ways to engage. By providing them a solid platform to engage (branded hashtags, contests, company posts, etc.), you are satisfying their need to be social and reaping the benefits. Consumers use a number of social channels to post their own pictures, videos, and comments, and having a team replying and sharing will encourage continuous activity. On the flip side, when consumer's efforts go unnoticed their eagerness plummets and activity fizzles out early on.
To miss out on this opportunity for a B2C event would be ludicrous!