it’s not only strollers, I have seen people playing ball in the street and i’m not evening talking about the fact that your not suppose to play ball on shabbos but…
If there’s a problem with playing ball on Shabbos, then educate people on that aspect of it — don’t conflate it with carrying.
In any event, I agree with you that there are people who might abuse the rules regarding carrying on Shabbos with an eruv — but that doesn’t detract from the validity of the eruv itself. If it’s valid, then it’s valid regardless of the fact that some people may choose to abuse it.
The Wolf