[Tagging] Tagging of community mailboxes (cluster maiboxes)

[wolfy1339]

 > it's also a real amenity=post_box ? as a tourist, I can find this box
 > on the postal operator's website and put my letter there?

outgoing mail boxes aren't listed on the postal operator's website.

As a tourist, if you happen to come across one of these, you are free to 
deposit any outgoing mail in the designated slot

 > or is it just a habit that people also put the outbound there ?

It's not a habit, there's a dedicated slot to put outbound mail

Here's a picture for reference, 
https://upload.wikimedia.org/wikipedia/commons/0/0d/CanadaPostCommunityMailboxes15.jpg

 > for me, that doesn't matter. it's a amenity=letter_box

I get that, since that is it's primary function.

How would we then let people know that outgoing mail can be put in the 
box via the outgoing mail slot? Would it be better to tag one 
`amenity=letter_box` and one `amenity=post_box`, or simply put it just 
under `amenity=letter_box`

I just want to make sure since there's currently around 4000 uses of 
`post_box:type=community` (which is the current recommended tag on the 
Canadian Tagging Guidelines), it would make up a quarter of all uses of 
`amenity=letter_box` that this is how the worldwide community feels.