I'll wager a guess in that for items such as a mass produced car, people will be cautious on bidding (for the reasons stated by SoCal above) and I don't think you'd see people using software to bid at the last few minutes.
However, if there is a hard to get item such as a particular Christmas toy or something that is new in the box (to reduce risk and is a known quantity), you may see some people use bid software to work the pricing in their favor and win the auction.
My wife just won a set of discontinued DVD's last week, but was sucessful with a last second (20 seconds to go) bid using just her fingers, keyboard and high speed connection. There was enough last minute bidding to keep things interesting.
I've sold a few things that really skyrocketed in value during the last 3 minutes of an auction. I typically start my auction out at the bare minimum of what I'd take. No reserve either and typically no Buy It Now. That tends to get people thinking that they might be able to get my item cheap. It then hits the 'watched' list and people are reminded via eBay that this item is ending (another good sales tool) and they may try to bid. Some people may get caught up in the excitement at the end of the auction and inflate the price. Good for the seller, bad for the buyer.
Just my $02. after using eBay for years now...
Jay
90 964