So, Gamestop likes their customers to reserve upcoming titles. They post "Coming Soon- Reserve it Now" on posters and game cases all over their stores, they have videos telling customers to talk to their "game advisors" about reserving whatever title they're talking about onscreen at the time, and their employees are instructed to ask every customer if they want to reserve something.
For just five dollars down (ten for special editions), they'll tell you, you can have a copy of the game waiting for you on day one, guaranteed to be waiting for you!
In fact, their employees are pretty much expected to get these reservations, and can face repercussions (up to getting terminated) for not meeting the expectations set forth by the company.

The funny thing is, and the point I'm meandering towards, is that according to their new policies, this "guaranteed" reservation is not actually a guarantee that you can get the game day one.
I used to work for Gamestop. When I started, we were expected to hold a reserved game for 48 hours. We told customers who were reserving a game that it would be guaranteed to be there within that time period.
Partway through my five years with the company, the mentality began to change. We were encouraged to "play the float", which meant to gamble a bit and sell into your reserved copies. They indicated that only about 65% of the reserved copies of a game were usually picked up, so we could generally be safe in selling into that other 35%. Plus, in many cases (like a big Madden or Halo release), we'd be getting more every day, so we were never in danger of selling out.
We were always advised to use our best judgement, though, and if we felt we were getting close to the wire we'd stop selling to walk-ins to insure our reservation customers were covered. The important thing was that the reservation customers could get the game we guaranteed would be waiting for them.
The policy continued to morph as time went on, and we were gradually expected to sell more and more, until it became clear that the reservation itself was becoming pointless.
Shortly before I left, Rock Band 2 was released. I ran a low volume store, so we only had 8 reservations for the game, and we only got 10 copies in for the Sunday release. This is not a large number, and we had gotten no emails to indicate when our next allotment would be. The extra 2 copies sold quickly, and we were hesitant to sell the reserved copies simply because there weren't a lot to play with. Customers were flowing in throughout the day to pick up their reservations, and we were turning walk-ins away.
We held the copies for the 48 hours, as we had promised our customers, and during those two days we didn't get any more copies sent to us.
On the day that the 48 hours expired, I had a visit from my district manager and regional director. We had sold all but two copies of Rock Band 2, which they felt we should have just gone ahead and sold without worrying about the reservations.
As the regional director told me, "I'd rather you sell through them, and have to deal with a complaint or two from customers, then hold onto them and wait for sales that may or may not happen."
I understand that it's a business, that they want to sell things and make money. Fine. However, what he expected of me was "Screw the people you guaranteed could get the game they reserved. Just sell them, and if somebody gets mad, deal with it."
I've been doing customer service for almost twenty years. If I guarantee a customer something, I fully intend to follow through on that promise. I don't like the idea of circumventing my integrity and just dealing with the fallout.

So I've been gone from there for a while now, but I still get information from various employees, and it seems that the practice is still in full swing.
With the recent release of Halo Wars, my former district manager ordered all of his stores to sell every copy to anybody, INCLUDING THE LIMITED EDITION, regardless of reservation. So, as they didn't want to get in trouble, they did so.
The store in question had, the last time I heard, three separate incidents of customers coming in to pick up their reserved limited edition game and being unable to do so. In addition, as these were "limited", the store was frantically calling other stores but nobody had free copies to share. Especially because other stores within the same district were having the same issue.
Great. So the game sold out. Congratulations. All it took was pissing off people that you had promised could get the game on the first day.

So, you can reserve a game, but if you're not right there first in line, you may or may not be able to get it day one. Of course, they do say that they will definitely get you a copy, often meaning that they'll get one from another store or wait for another shipment to come in, but by that point you could go to Target or Best Buy and just pick it up on release day.
Of course, if you ask a game advisor, they still swear that your reserved game will be waiting for you on day one, guaranteed.

Hell, I don't know. Maybe I'm old fashioned. Maybe my theories about customer service, in which you actually try to avoid complaints rather than take actions and then pretty much expect them, must be outdated.
Which, I suppose, is why I don't work for Gamestop anymore...