I have noticed that, generally speaking, in this part of the Pacific NW, coffee houses, pubs, restaurants... and their open mic hosts, who don't give a hoot about the audience noise factor, seem mostly uninterested in trying to do something or anything about it. The hosts are primarily in it for the money they receive. They don't go out of their way to apply guidelines on those in attendance, drinkers, eaters, socializers... to make their events better suited for the presentation of those venturing on stage with their various forms of entertainment. The scenes in this area tend to be a free-for-all.

First and foremost, the owners have their own concepts about what they deem will provide them with the best patron base and bottom line and since they pay the bills, their determinations are most often followed within the space. I imagine that makes it tough for an open mic host to apply their own concepts to their three hour events. Performers tend to get the short end of the stick, having to suffer with all of the contemporary distractions that usually accompany those venues.

Pubs and bars tend to be the worst about including distractions to appease their patron's desires. Big screen broadcasts of every sort of sport are common, as are pool tables, dart boards, various electronic gambling machines... Restaurants tend to have limitations on performer's volume, due to food and socializing being their primary features. They primarily treat anything like music as sonic wallpaper. Most coffeehouse's espresso machines tend to be primary sources of ambient noise to contend with. All of the above make presenting a live acoustic music open mic scene in most business spaces an uphill battle for players/performers.

All of the above said, I've been personally astounded when my musical offerings have managed to completely command the attention of an entire room full of alcohol fueled conversation within arguably the worst open mic stage conditions possible. Even when my personal folk music heroes failed miserably at the same task.