Allows you to manually add an entry to the arp cache that resolves the ip address inetaddr to the physical address etheraddr. what would happen if, when you manually added an entry, you entered the correct ip address, but the wrong ethernet address for that remote interface?

The answer in this question is that once the Adaptor or router received the destination IP address (even if we entered in the incorrect MAC address) the router or adapter would remove the IP address from the Ethernet frame and using ARP, would get the correct MAC address of the destination.