Why am I getting requests outside of my service area?

Technically yes, it does affect your search ranking; however, getting requests also affects your ranking, so if you get a request you have to decline, it's a wash.

As for turning up in the search results, the search algorithms err on the side of showing more sitters than fewer. Your range is just a circle around your location. So if they search just for the city name or for a zip code which is partially inside your range, you will show up in the results because Rover doesn't know at that point where exactly the user is and where they are requesting care. However, if they request the neighboring city or a zip code entirely outside your service area, you probably won't show up (though you still might if there are very few sitters in your area). They don't want to exclude you from the results without knowing for sure that you don't meet their needs. Same goes for requests for dogs outside your age or size range, or for dates you are marked unavailable. If the client just enters in the basic information without completing all their profile and search info, sitters who are not a good match will show up because the system doesn't know yet that you don't meet their needs.