Different Families, Different Rules

Teaching toddlers all the household rules can be challenging. Sure I want them to behave at the table, clean up their toys, etc., but that doesn't always happen. I have a few rules, though, which are non-negotiable: We don't bite, we don't hit, we don't push. It can be difficult for my daughters to understand why other children are allowed to do these things.
For the most part if another child pushes one of my girls, she'll simply move to a different area or activity. I think some of this comes from having siblings. If your sister is bothering you, the quickest way to resolve the issue is to take yourself out of the situation. But when you're in a confined space, say a preschool classroom, moving away isn't always easy.
From time to time I'm told this on the way home from preschool "So and so pushed me" or "The boy took my toys." When I ask "what did you do?" the answer is usually "nothing... but he was naughty." I have explained to my daughters that not every mommy and daddy have the same rules at home and even if they do not every little boy or little girl remembers the rules all the time. I'm not suggesting there are parents out there who think it's OK for their kids to bite, hit or push, but I know there are parents out there who don't discipline their children for doing these things.
On an outing to the local children's museum, a boy who was clearly older than my daughters pushed one of the girls out his way so he could use the activity with which she was playing. I didn't say anything. I just steered her toward another activity. A woman with the mom of the boy in question must not have seen what happened because a few minutes later she said to the mom "Did you see those four little girls? Wow. Look at how well-behaved they are." Do you know what the mom said? "Yeah, well, I bet she wouldn't have the same luck if she had four boys." It still makes my blood boil. I don't buy into the notion that boys are harder to raise than girls. Come to my house when my daughters are trying to do a live version of WWE. But that's a post for a different day.
My daughters are becoming better at understanding that regardless of what other kids do, they are still expected to follow certain rules. They're also becoming better at standing up for themselves. While they haven't hit back or pushed back (yet), they will say "Don't push me." I don't expect my daughters to be perfect angels... but I do expect them to do their best to follow my rules and treat their peers the way they would want their peers to treat them. Heavy stuff for a four-year-old.