I'm pretty sure that auctions that have the 
option to end early are marked.  For sure,
Yahoo auctions, not too sure about ebay
though.    

Many people are aware that auctions may end
early, therefore bid right then.  You obviously
have seen this auction before it closed, and
had the chance to bid on it at first viewing.   
Though, I don't know many sellers that would
close an auction prior to the date, but like you
said, it's her auction to do with as she likes.  
Also, this doesn't sound like the first time
you've been peeved that she closed early.  If
you knew that she tends too close 
auctions earlier, why didn't you bid when you
had the chance?