I had not looked at the page in some time. I do recall previous discussions in the forum (hopefully not just GHO!) that are in-line with what I described. PZ wrote the current page less than a year ago, but “inherited” much of the language from the parent global page. That page first got this language in Feb 2014, in a Kent Smith edit. Kent is our Wiki tech guru and a champ, so I don’t take his word lightly. However, 1) I can’t find a Wiki Updates forum post for this page for that time period, and 2) I suspect the terminology was not meant to be read so strictly, and shoudl posisbly have been more carefuly considered.
“Recommendation” reflects the fact that we know that they work; anything other than recommended should not be used without testing (and should then be recommended, discarded, or fixed).
“Convention” reflects the general approach we take on where to CONSIDER abbreviations.
Neither means that you must find a way to abbreviate, or that one overrides the other. To quote sketch (our most senior Global Champ), “when in doubt, spell it out.” Even if the recommendation and convention (to use the current terminology) both indicate an abbreviation, that doesn’t mean you must do it. It means you should consider abbreviating in those cases, and most likely you will abbreviate. But if you have a reason not to, then don’t, whether due to doubt (or certainty!) about whether it will technically work, or you just feel that it will be awkward or hard to read for the Wazer, or some other reason.
The rules as I described them are meant to abbreviate what can be abbreviated, without confusion, or wrong TTS. Ancillary parts of the name are less likely to cause confusion even if not spelled out, especially if they are very common names with very common abbreviations. The main part of the name is more likely to be difficult to understand and identify if abbreviated. More often, those common ancillary parts come after the main name, not before. Hence, why it describes suffixes, and why it may dumb down the rule to specify matching prefixes exactly; and also why the specific exceptions are given (though unfortunately, they are given as examples without a general rule to guide those examples).
As stated, I think the prefix handling in the wiki is bad. For one, we don’t always have consistency in the signs, and sometimes we don’t even have signs. For that matter, sometimes directionals (NESW) are prefixes (East Main St), but street signs may not include the directional at all. I’d rather see it follow the same rule as suffixes AND add a qualifier for both prefixes and suffixes, that if the street name is short and there are street signs that do not abbreviate, it is OK to spell out the prefixes and/or suffixes.