This is Jared, from Dr. NO's. I am the assistant manager of the store. I just wanted to give you a response to your complaints. I understand you were not expecting the requirement of a purchase for the event, and I am sorry you did not know about it before hand. However, the last game day at our store was run the same way. The reason for this purchase is to ensure that our regular customers have first chance at the events because space is very limited, and they are grateful for the ability to reserve their seats. Also, the purchase of the product does not have to be on that day; customers who are buying D&D products in the weeks leading up to the event and who express an interest in playing will have their spots reserved. One last reason for the purchase came about through the change in event style. Originally, D&D Game Days were meant to introduce people to rpgs through the event known as Free RPG Day; however, WotC strayed away from that when they started making them what are essentially release events for new books and held them more frequently. These release events are aimed at players that are already playing D&D 4th edition, so a majority of them are already planning on purchasing the new book from us.
The smaller turnout for the game day goes beyond what you are stating in your post. One of our more popular DMs notified us earlier in the week about serious health issues he was facing, and he regretfully had to cancel his game. Upon hearing this, we notified players who specifically wanted to take part in his adventure and they decided to wait until the next game day. Also, this same weekend, there was a convention taking place no more than twenty minutes from our location, which impacts customer turnout at times.
The final comment I would like to address from your post is the misinformation you received. You state: "The store clerk said it was something mandated by WotC, and that every other store running Game Day would be doing the same thing. He claimed that WotC needed the sales to justify the cost of printing the character sheets and maps and such." What I actually said was that the purchase needed to be made for reasons I stated above. I believe the other information you are stating that I said came from another player in the group that ended up joining into the conversation because I have no knowledge of WotC's financial investment into these events and would have never lied to a customer; that is just bad business. I had to attend to customers on the comic side of the store as the discussion of the purchase continued, and I am sorry I was not on that side to catch any of the factual errors that someone may have stated. To be clear, whomever you heard the additional information from is not affiliated with the store.
Again, I am sorry you fell you have been cheated. I know for a fact that the other DM and his group that joined yours had a wonderful time and fully expected the purchase of a D&D product; they also plan to return to the next event.