Download App Store app on one Mac to install on another? I am working with a client who lives in the country, and has absolutely poor Internet speeds. Even though the connection is "high-speed wireless" (I believe it's WiMAX based), he routinely receives about 20 KB/sec on a good day, and almost always less. In other words, think a dial-up modem with even higher latency. Normally, all this guy does is some basic Email and web browsing, and he's just the sort who's patient enough to deal with it. Not to mention, monopolies and ISP business dealings mean he's unable to get any better speed to begin with unless he went with a capped LTE link.

Anyway, this guy recently got a Mac, and is now beginning to enjoy the advantages. He just now discovered the App Store, and has been downloading some small apps. Apps that are say 3MB or so will download in 5-10 minutes for him, but as I said, he's pretty much fine with that.

Now, however, he made the "mistake" of buying a game that weighed in at 3.8GB. He's now looking down the barrel of a 8-day solid download, during which (due to latencies and such) he won't really be able to do anything else with his connection.

He asked me if there was any way I could possibly download the app (on my nice 100Mbit connection!) and give it to him on a burned DVD or USB drive. Of course, Windows vets will be used to this method for dial-up dwellers - the traditional "sneakernet". I explained the issues with the App store being intimately connected to the Apple ID, and he said he'd be glad to share his Apple ID password with me and then just change it afterwards. 

I do have a spare Mac that could volunteer itself to be temporarily registered to his Apple ID to download the app. The only thing I am not sure of is if downloading the app on my machine, transferring the .app package to a flash drive and copying it to his machine will work. 

I would just try it but since we're dealing with "live" data here (i.e. his account) I don't want to do too many "experiments", and also I would like to be reasonably sure before I schedule another trip out there, only to find out it won't work.

I do know Apple's crypto technologies are pretty deep and intense, and it's conceivable to me that each app download is somehow uniquely encrypted, to prevent obvious piracy. 

Has anyone else tried something like this, and if so, can it be done? 

Thanks!
I've tried it, and it works, provided that the app's makers don't put in their own special encryption system. There isn't even a limit of 5 computers per account on the Mac App Store (only iTunes and iOS), so you won't have to worry about that.

Edit: There's another question like this here. The answerer agrees with me.