If an animal has used the soil under the gravel for relieving itself or for territorial marking, the smell will remain under the gravel. I have the problem of a new pet cat using the soil next to a gravel path, and using the gravel to bury the feces, in the same area that was a territorial marking place for a previous cat.

If the soil under the path is "clean" you should not have a problem.

You might also consider growing plants that animals do not like to smell along the borders of the path. Look online for plants appropriate for your geographical area and the animals you do not want near the path.