That’s just common sense
Another wise guy who thinks he’s funny, and we don’t care if you judge us, but this really did made us laugh a little bit. It’s one of those dad jokes that makes you go, “ha ha,” and if there are any fathers around, they’ll probably find it funny, because that’s their kind of humor.
In a weird way, this little note might attract people’s attention to the fire notice, which is very important, so perhaps, unknowingly, this person was doing a great service to the community, while all he wanted was to be funny and have his 30 seconds of glory.