Occupational Safety and Health Administration (OSHA) states:
Safety guards must never be removed when a tool is being used. For example, portable circular saws must be equipped with guards. An upper guard must cover the entire blade of the saw. A retractable lower guard must cover the teeth of the saw, except when it makes contact with the work material. The lower guard must automatically return to the covering position when the tool is withdrawn from the work.

The Saw Guard Dog is not intended or to be confused with being a safety device for circular saws.
It is instead a mechanism that when used properly we hope will eliminate the unsafe practices of pinning or holding up the saw guard for making special cuts which could expose the saw user to the unprotected spinning saw blade and possibly cause unnecessary injuries.
As OSHA and other safety institutions have stated, it’s always important to check and test that your equipment’s operating properly before using it. This applies equally when using the SAW GUARD DOG, if it’s damaged and not letting the saw guard close automatically all the way over the blade then the saw should be unplugged from the power supply and it should be safely removed before using the saw.