What does Elmhurst require....
A couple of 2x4's with caution tape... Yep, that'll keep someone from falling in the hole.
Hold your nose and breathe through your... OSHA would have a field day with this.
I'll bet this orange plastic fence will keep curious kids from falling in this hole. I also like the 2x4's holding up what's left of the yard that the neighbor's fence used to be anchored to.
Do you think a little common sense would come in handy here?