Retrieving Your Lost Credit Card
This all-too-common problem is somewhat tricky to resolve, because the bar probably closed out your tab on the night you left the card behind. Did they include an automatic gratuity? That’s a 50-50 question, based on the discretion of the business. If they did, dropping a few extra bucks would be cool, but not essential; if they didn't, leave the tip now... plus a few extra bucks.
Drinking at an Open Bar Wedding
We ran across a fellow patron at an Irish bar who happened to be a professional caterer -- how serendipitous. He definitively stated that in his operation, gratuity is always negotiated at the top level at weddings, and that bartenders are not supposed to accept those dollars that get slammed down in the midst of shouting, “a little bit louder now!” If the bartender says they can’t accept tips, put it away; and if he looks at you like he's expecting a tip, find another bartender.