http://en.wikipedia.org/wiki/Round_robin_DNS Here is a good explaination. If two or more records, the dns server can serve up records in a different order.
Just remember to have the same machineKey should match so encryption / decryption of .NET works seemlessly. Also, if one VIP is down, the DNS address will still serve up requests since DNS does not know about the one dc being down. You could remove the A record from DNS, but cached records on the internet could try to send records there. W/o some type of smart load-balancing, some clients would try the DC out of load.
