I just looked it up and XenForo (the platform this forum uses) only supports 1 prefix at a time for a thread. This is currently being used as the component type prefix for the market section, which IMO is more useful than location.
Location tagging of threads in titles could be useful, especially since the suggested format for market threads is not followed very often, but this would be a pain to enforce and not have that much of a benefit.
Also if you have freeform tagging instead of a preset list, you face the problem of misspellings/alternate spellings, nearby areas, metro areas with multiple accepted names, which further decreases the usefulness.
So nice to have, but not feasible to implement in a useful manner.
Edit: to clarify, I'm not a part of the admin/mod team here. Just my two cents.