Since this thread is here, I thought I'd take this time to post some of my thoughts on the morality of the mug issue.
Once I found out what the official policy was, I decided to comply, so don't take any of my thoughts as indications that I, myself, use my old mug for refills, because I don't. But for those who get all self righteous towards those who do, let me ask you a few questions....
Have you ever, or do you currently: Use the office stapler to staple things for personal use? Use an office ink pen to write personal notes, such as, say, a grocery list just for one example? If you do that, do you use office paper to write it on? Do you ever play on the internet while at work? Do you ever use the office printer to print things for personal use? Do you ever, by accident or on purpose, take home a cheap ink pen from the desk, and then not worry about bringing it back because they're a dime a dozen and no one cares? By accident or on purpose, get to chatting on break and end up taking a few extra minutes than you are entitled by company policy? Get stopped in the hallway at work and carry on a personal conversation on office time?
For those who get on a moral high horse and cast stones at those who use their mugs for refills on other visits, take a look at the above questions and tell me honestly if you can really answer "no" to all of them.
You see, the above are all examples of ways that each and every one of us can be guilty of "theft" in the most minor sense. Whether it be time theft by taking a few minutes too long on break, or visiting in the hallway on office time, or theft of a single staple or sheet of paper, there are a multitude of ways in which we all "steal", but do so in such a minute quantity that we don't think of it in our minds as stealing and neither does anyone else. Yet, in the most technical and black and white sense, if you use one piddly little staple from the office stapler, you have stolen company supplies for your own personal use. I don't think any of us would dream of walking into the supply closet and taking out a whole container of staples and taking it home with us. I don't think any of us would dream of making off with an entire ream of paper to fill our printer at home. Yet, how many of us may be surfing the internet at work and print out something that we see that we think is cool? Or check our email at work and get a funny joke that we want to print off? Technically, that's stealing. That's office paper and office time that you're using for personal use. Even if you bring in your own paper, you're still "stealing" that minute amount of ink to print out whatever it is that you're printing.
IMO, it's not that much different when discussing the mug issue. Trust me, WDW, in all the billions that they rake in througout the year, is not losing any money on those fountain drinks that people fill last year's mugs with. The amount of money that you're "stealing" from Disney is probably on the level of a single sheet of paper that you steal from the office to jot down personal notes, or the ink that you use to do it from the office ink pen.
Now, am I encouraging people to violate Disney's refill policy? No I'm not. I'm just saying that before you get on a high horse and pound on your chest saying "what a good little boy am I" and cast judgement on all those desperate outlaws stealing drinks, think of the many ways that you yourself may be guilty of minor theft, such as in the examples I gave above. It kind of puts it into perspective, IMO.