We also have a very picky eater (beyond picky, really)
You have a couple of options...when you're at Counter Svc restaurants you can split up and go thru separate lines. One of you order your own adult meal and the other order two adult meals (one for you and one for your child). That way you can just avoid being questioned about it if you're worried they will challenge you. Actually one time we were together in line and I didn't realize I was ordering chicken strips for ds off of the adult menu instead of the nuggets off the kids menu, until after she had rung it up and she didn't care...so it probably really depends on the cm's (and probably how busy they are because that time they were really slammed).
Or, you can skip ordering a meal for you child at all and just let him eat off of your plate. You'll find there's plenty of food to go around so this might just work for you a lot of the time.
The credits are all lumped on one "account" linked to your room cards and they are not split up as child credits and adult credits so it is pretty flexible.
Since we have a very picky eater too, we decided on this next trip to eat at more of the buffets so we won't have to worry about the children's menu nearly as much. Recently they changed the kids menus to make them a little bit healthier so if your dc likes fruit and veggies you might not have any problems at all.
HTH.
p.s. yes, the Dining boards have lots of info about this so I also recommend heading over there as well. Here's one thread about ADR's for a picky toddler
http://www.disboards.com/showthread.php?t=1270439 you might be interested in. hth.
