No problem. Your vehicle in stock configuration is designed to "crumple" or collapse in the event of an accident. Let me give you an example:
Stock:
Let's say you hit something at 10 mph with your bumper. What will be damaged? Well, your bumper cover, your inner bumper reinforcement, maybe a fog lamp and the lower grille.
With grille guard:
Same impact as above but due to the A) mounting points and B) thin material of the grille guard this impact will, in addition to the above damage, bend back and damage the hood, top grille, fenders, headlight, etc. Since it covers a larger front area it will just bend back and break or dent things that would not be damaged if you just had the stock bumper.
The grille guard would be fine for keeping twigs or brush from hitting the front of the vehicle. Any real impact beyond a few mph will render it useless. Police vehicles use them for pushing which is quite different than an impact.