Use a Mac App Store free app without having to associate/login to Apple ID? The scenario:

I'm working on a friend's Mac. To proceed with the task at hand, I need a specific tool. This tool is available for free (and does not use in app purchases) from the Mac App Store, but isn't available as a direct download from the developer.

I do not wish to log into my own Apple ID on my friend's Mac, for a number of reasons: having to deal with de-associating and re-associating my friend's ID with his machine, the fact that there is an apparent limit as to how many Macs can be logged into the App Store under a single account, etc.

My friend is not present and thus I do not have his Apple ID password to download it under his account. It wouldn't be a reasonable request to me to ask my friend to provide his Apple ID password to me. (Assume that before giving me his machine, my friend set his local system password to something generic so I would be able to know it, but has obvious good reasons to not do this with his Apple ID password.)

Another scenario:

I am at work and just received a Mac. The IT management says that employees are permitted to install any apps onto the machine as long as they are free. (So, for example, I'd be allowed to install Homebrew, or stuff from SourceForge, etc.) However, the machine is logged into a "corporate" Apple ID, and thus I cannot re-associate it to my ID even temporarily. Also, I would not be able to "purchase" the free app under the corporate ID as I would not know its password.

In both scenarios, I do have local administrator rights to the machine. 

In these scenarios, is there a way to use the free app from the Mac App Store on the machine in question, without having to associate that machine with my own Apple ID, or purchase the app under someone else's account?
An Apple ID in OS X is attached to the account, not to the machine so you can create a new account, use your Apple ID, use the app, then delete the account when finished.

Another alternative is to use another Apple ID.  There is nothing stating that you can't have more than one Apple ID.  Just create one for when you are doing tech work like what you are doing now and use that one.

Finally, you can ask your friend to sign in and use his account so you can download the app under his profile.