We sometimes have free stuff to raffle at an event. We have tried various ways to award free stuff to participants on the night - tweeting a picture or something. This is not always successful - and the current thinking is as follows - as a guide:
In any case, I propose a different system for putting oneself forward for the ticket(s): anyone who is interested approaches the emcee and puts their name "in the hat" for a random draw at the end of the night. More tweets does lead to better marketing for us but it's difficult to know if those people are specifically interested in the tickets or even available on the date in question, so this way is less ambiguous.