I get your point OP, even though after reading the whole thread and re-reading your opening post I have to agree with the others that your wording painted an ambiguous situation that led itself to the two contrasting interpretations by everyone up thread.
First at all, I think that rather than asking for advice about where to draw the line about “rough-housing” behaviour, what bothered you the most was the over the top reaction by the mother of the 2 year-old and you wanted to know how to deal with such over the top reactions when you said that “something of this nature seems to happen every time we go”.
I can only comment on the isolated incident you describe, and definitely it was not your fault (although I wasn’t there, and only have your side of the story).
I can see that the 2 year-old being knocked down the one time by your children was an accident. You said your 4 year-old immediately apologized and that your DH told your sons to tone it down as they could accidentally hurt someone.
This is in complete contrast to the 8 year-old announcing he is going to “karate kick” your 4 year-old in the face and then doing it. Not only there is deliberate intention to hurt another child, but the child who did this was also much older in age and should know better than to do this kind of thing.
Despite the “karate kick” incident being more serious in nature, you described how you calmly dealt with it and that the oblivious mother didn’t even become aware of what had happened. I personally think you should have mentioned it to her, because otherwise how can she reassess her parenting and take corrective measures at home if she doesn’t even know what her 8 year-old son is up to?
And then, on the other hand, the subsequent incident that took place when your two sons were playing boisterously with each other and accidentally knocked a 2 year-old that they hadn’t noticed had entered the area, despite being milder in nature (i.e. not deliberate intention from your sons to hurt the 2 year-old, and immediate apology when this happened, plus father being aware of it and exercising parenting to reinforce correct behaviour from the children who caused the accident), it was the one incident that elicited an over the top reaction from the 2 year-old’s mother.
I can totally see how you felt. So, as someone else recommended, have a well-deserved glass of wine and put it behind you.
Unfortunately, there isn’t much you can do about other parent’s reactions. Just as you cannot be expected to watch over or parent every single child in the soft play area (not your children, not your parental responsibility), you cannot expect to raise the levels of parenting of everyone else there and expect their reactions to be like yours would be. Everyone else is as they are, and you just have to accept it, and grow a thicker skin like someone else up thread wisely advised you.
Obviously, you do the best you can to keep your children out of harm, and make sure they don’t harm other children, like you seem to be already doing.
Whether the previous incidents on the other occasions that you mentioned are also just small accidents that fall into the “boys will be boys” or “kids will be kids” category; or are actually a reflection of your own children’s behaviour, I cannot comment on that because I don’t have the details.
And what is wrong with the expression “boys will be boys”? (By the way, English is not my first language so I might be missing something in translation here).
I actually agree with LittleLionMansMummy’s post. Even though I am not claiming to be an expert in this area, I have read several books on raising boys, and it is not the first time I hear about the evidence that suggests that rough play could be beneficial for children.
And I know my personal sample is small, compared to the ones they must have used for this kind of research, but I am the mother of two boys (1 and 5 years old). Among my extended family (nephews and nieces) there are a total of 8 boys in contrast to 2 girls, and all I can say is: Oh dear…
Every time there is a family reunion, trip, Christmas, etc, I can see first-hand how boys are so different to girls. Plus, I can also see how friends with only daughters similar ages have such a different experience to ours dominated by boys.
Obviously, not all boys have the same level of boisterous behaviour and like the same level of rough play. It’s more like a spectrum, with different children being at various different points of the scale. But I am not deluded that there is no difference between boys and girls.
Anyway, that has nothing to do with OP’s post (I just wanted to mention it because it has been my own experience). And whatever biological difference between boys and girls, it is not justification for over the top rough play that ends up in someone being hurt or antisocial behaviour.
In response to your question OP, you have to draw the line yourself. You have to decide when you think rough play is over the top and could end up in an accident, and make sure your boys follow your rules for “rough play”. And bear in mind that your line might not be the same as the one of other parents. When playing with other children your boys need to be extra careful, and possibly avoid playing rough if the other child is too young, not up for the same level of roughness that you allow, or has a very sensitive parent. Not a straightforward one-fits-all recipe for “rough play”. More like trial and error until you get the line to a level you and your boys are comfortable, and that you think it would prevent accidents between your own boys and any other children.