Many places also (used to) have sign saying 一見さんおことわり which roughly translate to "first time visitor not allowed". A little bit up to interpretation but usually in the scope of:

* store only for patrons, but welcome if you come with patron.

* anyone welcome but if you're only coming once (tourist etc), please don't (destroy the vibe).

For obvious reasons foreign tourist couldn't get this so many places just put up a "no foreigner" sign. You'll still see local foreigner sometimes hang around those places though