How can someone tell if I made a new alt?

[LakodaRayne]

I made a new alt and my friend knows it.we don't live in same house. We are partners in SL under other alts.

I wasn't even logged in as this alt said it showed up in contacts?? And can tell the name I created it under.

Howis he doing this?

[Marigold Devin]

Was it a bluff?

Did they tell you the name of this alt they suspect you have made?

If they do know the name of the alt, maybe you gave it a predictable name, or your alt is in very similar groups to yourself.

[Lindal Kidd]

He can't tell, not for sure.  But he can, like Sherlock Holmes, deduce the new alt from subtle clues.