As rjk said, if you keep your url safe (not post it anywhere online) google can't find it.
I gave an example. The right person will understand this.
I can also randomly try 1000 different instawallet url-s and publish them on a website, but that doesn't mean any of them are legitimate. Actually, it is a lot more likely you're going to be killed by lightning the second after you read this than it is for any one of those 1000 accounts having any bitcoins on it.