In reality, it'll only use one at a time to sync to, based on some server quality calculations I don't know. The others are only in case it loses connection to the one it's using, or if the one it's using starts to be of a lesser quality. However, if he's got a machine sitting right next to it that's a stratum 1 server (meaning it's connected directly to an official source), it's not such a big deal, unless that machine is down a lot.