Revenge hits can be made regardless of where the player is. I know this because I did a revenge hit on a guy who stole my map piece today, and he was active standing beside me in the city, as we both appeared to be waiting to see if the Fair Lady would pop back up on her own. Also, if you win a revenge fight, you can win coins and credits just like a normal attack as well as additional reputation if you haven't reached your cap for the day yet.