Wedding Registry: What if you don't need more stuff?

I had a reporter contact me from a local television station this week about what couples should do if they don't want to register for gifts, but would rather ask their guests for cash. My first reaction was 'yuck, that's almost like asking your guests to pay an admission fee to your wedding.' However, I have had clients in this situation and here are some ways to get around this in a more etiquette-friendly fashion.

1) Don't register for anything at all. Most people will end up giving you a monetary gift because they aren't sure what to get you.
2) Our Wishing Well offers couples an option where they can put together a wish list of items they'd like to get, and their guests give them monitary contributions toward these wishes as their gift. It's free to sign up too and your guests only have to worry about one registry versus multiple ones. You can put it on your wedding website as well, which is great.
3) Bed Bath and Beyond allows you to return any item on your registry for cash, no questions asked, within 90 days of your wedding. Most other stores will give you store credit.
4) You can also do a honeymoon registry. Websites like Honeyluna let you choose things to do on your honeymoon, and your guests will cover the cost of it. For example, maybe you want to take a day to go snorkeling with dolphins, or go on an excursion of historic ruins, get a couples massage, or rent jet skis. You can register for these, along with the honeymoon itself, with a honeymoon registry.