Not content to have only the keys to your front door, Amazon.com (NASDAQ:AMZN) also wants the keys to your car.

Following the start of the in-home delivery service called Amazon Key, the online retail giant is launching a service that will deliver packages to your car, whether the trunk or other cargo space. If your car is parked at home, work, or another publicly accessible area, and you have a 2015 or newer General Motors (NYSE:GM) or Volvo vehicle equipped with OnStar or On Call, respectively, you can get packages delivered using this method.

An ad for Amazon Key car delivery service showing a cell phone and a delivery guy with a package waiting by a car.

Image source: Amazon.com.

Keying in on convenience

For people comfortable with giving strangers access to some of their most private spaces, the Key service continues to make Amazon the most efficient, convenient, and perhaps fastest delivery option available. And Amazon insists the new service is safe, so you don't have to worry about the delivery driver making off with your ride.

Before requesting vehicle access, Amazon Key verifies the delivery driver, the car, the driver's location, and that the package being delivered is the one you ordered. Amazon Key only obtains your vehicle's location on the day of delivery, and because the driver never gets an access code or the key to your car, there's no need to worry he can come back at a later time to take it.

Moreover, the Key service confirms that your car is locked before the driver leaves, and in the event it isn't locked, the service automatically activates the locks.

A daunting level of trust is needed

There are obviously benefits to these delivery services. So-called "porch pirates" stealing unattended packages has become a very real phenomenon, which in-home delivery helps to thwart. It also gives Amazon more access into your life -- and more data it can collect about you -- while creating a greater bond of trust between you and the retailer. And it all comes under the cover of convenience.

Of course, letting a stranger into your house when you're not home -- or even if you are there -- takes a great leap of faith. A survey of 2,201 consumers by Morning Consult found that 68% of people were uncomfortable with letting delivery drivers into their homes and 53% were "very uncomfortable" with it. Although those 18 to 29 years of age were twice as likely to be comfortable with it than those 55 to 64 years old, more than half of even that younger cohort was still uncomfortable with the idea.

Giving access to your car's cargo space likely reduces the stress level for many people, because you can make sure there are no valuables there. But short of removing everything important from your car, it's not completely secure, either. Not every car is a sedan -- hatchbacks, SUVs, minivans, etc. give full access to the interior when the rear hatch is opened. Many cars have folding rear seats that are accessible from the trunk, so storing your valuables in the passenger compartment won't make them safer either. (It's probably not a good idea to do that anyway.)

Although the chances of an Amazon driver rummaging through your personal effects is probably low -- or that he will hot wire your car to steal it -- there remains the increased risk of vandalism to a vehicle by having a package delivered to it.

Delivery may not actually be the point

Amazon Key seems like a solution in search of a problem. If we're at home or at work, are we really so much farther away from our car that we can't just have the package delivered to us? And if we're out at the mall, do we really need Amazon delivering packages to our car?

It's true people seem far too willing to give up their privacy to social media networks in the service of staying connected with family and friends, but that doesn't mean we need to extend it to the businesses we shop from.

The universe of Prime members this service is available to is already strictly limited due to the fact it's currently only available in 37 states and you have to have a specific brand of car equipped with a remote vehicle service to be eligible. For those reasons it's not going to be widely adopted. Although other car manufacturers like Ford that come equipped with Sync could be included, Amazon doesn't even need it to be a huge hit.

What the in-home and in-car Key service really shows consumers is that Amazon is willing to do what it takes to be the most innovative, quickest, most convenient package delivery service around. Whether someone avails themselves of the opportunity is immaterial, as Amazon still drives home the point that you need and want its services -- and that may be the most important benefit of all for the company.

John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Rich Duprey has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Amazon. The Motley Fool recommends Ford. The Motley Fool has a disclosure policy.