I wouldn't worry about anything, these are freak things that happen in restaurants from time to time. There is no need to call to make sure they will be open.
Central Florida is the lightening capital of the world, if the hood system (that controls the fire system and the gas for cooking) gets struck, it may take several hours to fix and operation is not possible. Just one scenario.
Little things like this happen all the time, in WDW and not. No restaurant would want to stay closed unexpectedely, I'm sure this was a one time, unexpected thing.