My belief is that if someone uses the "Release" mechanism, that is covered by
the sentence which states:  
"If the upstream does create tarballs you should use them as tarballs provide an easier trail for people auditing the packages."
By creating the tag, upstream has clearly indicated their intent;  who are we to second-guess them?  
The commit hash part comes into play when a Revision or Tag has not been created.

I also added some verbiage to my draft which discusses your point about the different naming conventions that 
you have observed.  

On Tue, Jun 23, 2015 at 1:16 PM, Michael Cronenworth <mike@cchtml.com> wrote:
On 06/23/2015 12:09 PM, Gerald B. Cox wrote:
I'm working on a revision here:

I'll take a look at that and see if I can clarify since I'm already working on it.

Thanks, Gerald.

Are you proposing to include or exclude the URL types that use the "Release" mechanism? Some interpret the guidelines to exclude them, but as I noted many packages interpret they may include them.