Chaulking around base of toilet?

We are adding a full bath in the basement. My husband says we need to do this since the shower (step-in shower, so it's a curb, not tub) is right next to the toilet. He says that if water gets under the toilet,(either from the shower or a flood in the basement) it can mildew. The toilet is white and the floor tile is a cinnamon color, he plans to use whilte chaulk. I have never seen this done (none of our other toilets have chaulk) and am worried it will look bad. Is this ever done?