I am an
ultra picky eater* and have ordered off the kids menu for myself with never any problem, not to be "cheap", but simply to get food I like that wasn't on the "adult" menu, like macaroni and cheese, and small cheese pizzas at restaurants that didn't serve "adult" pizza, etc. I'm sure they were happy to have my business, if the alternative was me just ordering an ice cream or something to drink!
* My taste in food makes some little kids look like ultra-sophisticated food critics, by comparison!
(And since I became a vegetarian, ruling out (plain) burgers, fried chicken, fried shrimp, and (plain) hot dogs, finding food I like is even more difficult). Of course, when I'm by myself, I usually bypass table service all together, and usually stick with pizza and/or fries, (and sometimes kid's menu mac and cheese) from counter service, and a plethora of snacks throughout the day, such as popcorn and ice cream. But it's nice to know the kid's menu options are available to me at the table service locations.