Can someone out-snipe me?

Of course. The highest bid always wins. This rule supercedes all others.

However...

In the entire history of our sniper, and over million snipes, there has never been a duplicate attempt on the same item.

You might have a better chance of winning the California lottery, than to actually have been out-sniped by someone, even if they are using another service.

Bid aggressively if you want to win!

Remember: Your bid is kept a secret .. until it's too late for anyone to counter-bid!