Multiple players playing Halo 3 on one xbox 360 onto live?

[airdogspace]

I have seen a couple of times when I'm playing online that two (or more) people have the same name, just with a number behind it. So for example I'll see a tubaloth, then a tubaloth (1). I assume they are on the same box, but are the using the same xbox live account? how do they do this? Thanks

 

[nate w]

they are using the same account on the same box