Theres more than one story of parents being arrested for allowing their kids to chalk sidewalks and there have been some hefty fines as well. Its against the law in many places. You can be subject to arrest for chalking on public property. The NYPD has been known to enforce a New York City law that bars writing on any public property, including sidewalks.
It doesn’t ruin my day chas veshalom but it does annoy me and especially the fact that frum people take a part in this. I guess some people are just so immune to breaking laws and caring about yenem that they are in the “everything is ok” as long as my kid is occupied stage. Thats totally anti Torah thinking.