I have a 3.5yo, and I'm rather strict with her. She needs to listen right away, she eats what I serve, and I follow through on all consequences. That said, she learns a lesson quickly, so it hasn't been difficult. I stick to natural consequences (I wouldve done the ice cream line walk out too, though only if she was warned) and remind hubby often not to threaten, just do it. If she throws a toy, it goes away up high (so she can see it and want it, but not get it) for at least a day. She's a dream to travel with because she's well behaved, and we can even go to fancy restaurants as a family. It's paying off already, so I don't care if friends think I'm too strict.