1. Every family, including those with newborns, has a right to dine out at any restaurant of their choosing, as low-brow or high-class as they come, within legal rights of course (no celebrating Buster's 4th birthday at an Irish Pub).
2. You can't expect kids to be mutes throughout an entire evening, they're little balls of bound up energy which is often exaggerated with special needs children. But, if they get whiny or restless, you should take them outside to be disciplined, calm down, cool off, finish crying, etc. If the child cannot stay calm and quiet, then perhaps it's time that family asks for a to-go box. It's that simple.
We have a 5 year old and for the most part she's very well behaved. But sometimes, she gets bored (especially when waiting on our food) and can get restless. She never screams and cries, or even cries at all, but you can tell she'd rather be running and jumping around than sitting there waiting on food. So we try to take a proactive approach, we'll bring an activity book for her, or we'll play games (I Spy, for example) to keep her occupied and focused. She knows not to get up from her seat and especially knows not to get up and turn around. If she ever acts up to the point where it's bothersome to other guests, then our problem does not need to become their problem, and we'll leave.
A right? You do know it is a private business and if they wanted you they could toss you for unruly kids if they wanted to.