Firstly, you're wrong. If you go to apple.com/orderstatus you pre-sign your order once it's shipped. Know your facts.
I have pre-signed many a times for Apple products using the Apple website "pre-sign" form. Although it has always been with Fedex. I followed the directions exactly as presented and the driver still won't leave it. I've asked them before why they don't leave it when they came back around again and they said even though I pre-sign Apple still doesn't want them to leave it without a person receiving it. Most likely it is driver preference. My UPS driver always leaves everything up to this point and I've never had an issue. Furthermore, I can't remember receiving an Apple product from UPS before either.
I will note I live way out in the country where there is an extremely low chance of theft as well. I don't know what Fedex's problem is.