I live the cliche. I work as a bartender (mostly for a chance to get out of the house) two or three nights a week. When I look at a tavern scene, therefore, I look at it in a different way. If it's not realistic from my years of experience in the business, it gets on my nerves.
First off, if you cause trouble in my bar--out you go! It doesn't matter if I pull the stick out from behind the bar and yell at you or if I call the trolls hanging out in the back room, there will be NO fighting in the bar. Things get broken. That's expensive. And trust me, no one in their right mind goes into the bar business with any sort of tolerance toward things that cost more money.
Second off, it's a rare drunk that gets violent. Most of the time they just think they're funny...and that's no reason to kill someone.
Third, if a weapon is pulled in a crowded bar it certainly isn't going to be bigger than a dagger. Longsword, battleaxe, crossbow? Not likely.
Fourth, drunk people have a habit of trying to break up other drunk people when they're fighting. At that point, whether it's a real bar or ye old fantasy taverne someone who is not drinking intervenes. in my bar,it's the cops. In a fantasy tavern, it's more likely the security trolls in the back room.
Finally, the wise old tavern-owner/sassy, buxom barwench stereotypes. Both have a hardcore basis in reality. Sassy buxom barwenches sell drinks, and that tavern owner is wise enough to know that. In the long run, though, to be successful in any business that deals with alcohol someone who works in a tavern has got to be level headed and cool in an emergency. And, no one goes into the alcohol business without planning to make a buttload of money. money is the bottom line. period. No one deals with drinkers just for the fun of it. Trust me.
I've dealt with more than my share of bar fights. For me, it's get the drunks outside then call the cops. Occasionally I have had a bit of fun accidentally hitting someone with the stick (a depression-era billy club the original owner got from the beat cop after Prohibition ended and the illegal still in the cellar was replaced with totally legal beer) but the rules for barstaff everywhere are pretty much the same: restrain and remove. In the parking lot they can beat each other senseless until the cops show up, just get them away from the mirrors! I can remove a drunk more easily with two fingernails and an earlobe than I could with a sword.