I am all for them in the right circumstances. Usually I would pick a theme for each day. Our favorite characters, all one movie (and not even all Disney), Soda-pop, football jerseys, concert t-shirts, etc. You get the idea. It made great family photos. You can pick up these shirts at about any store that sells t-shirts.
The best time of all though. (Forgive me if you've read this before because I have posted it before). The Incredibles came out but wasn't released yet for home. I went to the
Disney Store in the mall and bought 5 red Incredibles shirts. We had our young niece with us, who has long black hair. She and my youngest son were about 6 and our older son was 9. The boys also had red Incredibles varsity jackets, and my husbands was black. All 3 had the incredibles logo stitched on the back.
The entire day, everywhere we went, CM's and Characters were pointing us out and posing for pictures. At the end of the day I had a stack of the cards to go get our pictures (remember this was before they could scan your card).
Needless to say, the kids still talk about that being their favorite trip. And it's 2nd in their all-time favorite family vacation. Which is crazy considering they've done Disney a ton of times and they've been all over the world.
And it was all because this mom had the crazy and often criticized idea to put the whole family in matching shirts.
I can also point out it was the month that the 75 Mickey statues were at the park. We naturally wore our Mickey Mouse t-shirts one day and posed with every single one we could find. I have a few collage frames that hang in my staircase with all of those pictures. The kids did great and posed to match whatever the statue was decorated for.