Yes, otherwise the "hot dog and coke" could be construed as "pay for services." Sheesh.
Like Bob P just said, I think District is where they draw the line. Many Little Leagues do not have qualified "free" umpires at the local level, so they have to employ paid umpires. Once an all-star team advances to the District level, the volunteer umpires are a dime-a-dozen. Scratch that, 10 cents less a dozen than that!