Probably the most awkward thing that passed spell check, but not the grammar police. This appears to be part of the standard dog park signage, and is part of the dog rules for the High Park area of Toronto. You can look at their full manifesto of conditions for dogs in High Park here.
And it appears that what this signage is trying to say is to fill in any holes that your dog digs up, because someone coming in the evening could trip and fall in that hole.
While Twitter had a field day with this signage suggesting some very inappropriate replacement wording, this is actually a Toronto Municipal Code Bylaw, number 608 in fact. And sadly that regulation states does state “Dogs that dig holes must have owners fill them in immediately.”
As the Toronto Star noted “It’s a bit of strange sign, right? If I’m reading it right, it suggests that dogs are allowed to dig holes, but only if they agree to notify and compel their owners them to fill them immediately.”
Of course the Dictionary people could not resist and they get the final word. Merriam-Webster wrote on twitter about the “broken” grammar asking followers to “Reword this sign to make it sound less weird.”
Which sounds weird in itself.
The wording of the sign and the bylaw are ridiculous, because it means that an offence or violation is only enforcable against the DOG!
Good luck with that!
Fact is, dogs that dig holes need to be kept in the loop. It is the dog owner’s responsibility to keep them up to speed.