My daughter did this tea party in January. Parents are encouraged to take pix before and after, since they're not allowed in during the party. The table set-up is DARLING - cute pastel and bright mismatched teapots and cups all down the middle with little wonderland character decorations.
If I'm not mistaken, the kids yelled "No peeking!" or something like that when parents tried to peek in. It was cute. They were served lunch and cupcakes, I think, and then eventually the parents were let in. The kids all pretended to be asleep when the parents streamed in and then they all woke up with a big "Surprise!" They all had little flower bouquets that they made for (and presented to) the mommies. On the table in front of them was their picture with Alice and the Mad Hatter (making a goofy face) in a "Grand Adventures" folio-type thing, with their autographs on it as well.
In the pictures I have (from after we were let in), my daughter is grinning from ear to ear. She had a great time.
I am overprotective to a fault. My daughter was 6 at the time, extremely outgoing, and actually had a half cast on her leg (so she wasn't going to do much running!), and I was still a little worried as my husband and I had lunch at the GF Cafe. I can say this: it is in 1900 Park Fare, which, once the doors are shut, is completely enclosed. The kids are going nowhere. It was well supervised. I don't recall the exact number of kids or CMs, but once I was let into the room at the end, it was clear to me that my daughter was safe as kittens while she was there. And again, she had a great time.
I will not let my daughter go into our suburban front yard by herself. She can't leave our backyard unless her mommy or daddy goes with her (another adult will not do

). She is not allowed to set foot in a parking lot unless she's holding my hand. The moment we exit a store, she must hold my hand. I don't even like her having play dates at friends' homes when I'm not there (something the other mommies in our social circle have no problem with). I am nervous when we're at the park or the pool (and she's a very good swimmer). I have serious overprotective issues.
Every child is different, and no one knows your child better than you. Some 4 year olds are very mature and would be fine. There's also the issue of how the parent feels about the activity. If the stress will take a year off of your life, then don't do it. It's cute and fun, but it's not worth that!
If your child wants to do it and you feel comfortable with it, I think it's a great experience, and I would recommend it. Honestly, for whatever reason (erroneous or not), I feel safer with my child at Disney World than anywhere else. I'm still overprotective there - I just loosen the reins a little bit.
