So the first thing you do when you arrive at any destination is load up and go shopping? Sounds very inconvenient to me and that's assuming you are probably travelling alone or with a companion. Add kids to the mix and things get worse. I take things in 3 oz bottles and can't remember the last time anything exploded due to altitude. At most, some might squeeze out into the ziploc. I guess occasionally, lodging will have a little kiosk open until 6pm that will sell you a small bottle of sunscreen for $13.
It really isn't that big of a deal. I don't pack "essentials" either, unless I know that a place won't have what I need (stick deodorant is a good example of this).
Most people will check into their hotel first-thing anyway. A 10 minute diversion to stop at a convenience store isn't as bad as you might think.
