Oh no, I hope that they didn't change their policy. We were down in Disney this past March and April. Our DD was only 7 months, so she really wasn't sitting in a highchair yet. We have a stroller that reclines, and were able to bring that into all of the restaurants that we went to.
O'Hana
Flying Fish
Spoodles
Beaches and Cream
Chefs de France
Cinderella's Royal Table
1900 Park Fare
Boma
50's Prime Time Cafe
The following restaurants had infant seats.
Chef Mickey's
Concourse Steak House
Just ask as you check in if you can bring in the stroller. If they are not too crowded, then maybe they can acommodate you. Good luck, and have fun!