I've never done it myself but had to pay a tab for a friend that was drunk, went to the bathroom and never came back. I paid her tab and looked all over for her for 10 minutes. I found out after I got home that she had been taken home by someone she had met that evening. He called me from her cell to tell me she got sick in the taxi and he was just leaving her apartment. I went to over to check on her. She was so sick that night and the next day that I never had the heart to ask for reimbursement.