One of my big biggest pet peeves is when someone dismisses another's feelings or concerns with "life isn't fair". It's condescending and rude.
I do understand the annoyance factor and safety issues with kids who are rougher and more intimidating. This concerns me with all my kids. In fact, our homeschooling group banned certain types of physical activity from our "family day", and started another gathering time specifically for that kind of physical activity. What they didn't do was segregate the ages. So I can choose what's appropriate for my bunch; someone else isn't making that choice for me. It would suck if I was officially prohibited from bringing my older kids to the more mellow gathering, and from bringing my younger kids to the wilder gathering. We'd end up being able to go to neither.
What's funny is that my experience has been very different from that of most people here, it seems. When we go somewhere where there are kids of different ages, it's almost *never* that I worry about the bigger kids, who usually either ignore my younger ones or are kind and accomodating. It is usually kids of the same age
who make trouble. Personally, I would much rather my two-year-old have all older kids to play with than a bunch of other two-year-olds whose mothers aren't watching them either, as is too often the case. Just yesterday, in a play area, the child who was being aggressive with my daughter and made her cry? Another two-year-old. I've lost count of the times I've seen little kids throwing sand at each other, or taking each others' toys, or knocking each other over.
I have to admit though that my gripe isn't even so much what is to me a weirdly artificial segregation (by ages but not play styles.) I don't begrudge people being comfortable however they can manage it. What bothers me is when there is no accomodation whatsoever for people who don't send their kids to school and who have kids who fall into different age categories. It's completely either-or in many cases. What about making a smaller age-specific space with a larger activity area, so that parents can watch all their kids at once? At our library in the kids' section, there is a place that is obviously for little kids, and another sectioned off by low book-cases for bigger kids. They don't mix unless they specifically want to be part of one vibe or the other. It works great.