It doesn't look
like a mistake. It doesn't smell like a mistake. In fact, it seems like exactly the right thing to do: Who doesn't love the lady with the tray of daiquiris? But according to contemporary research, when people do a favor for you, they tend to subconsciously justify their actions by assuming they helped you out because they like you.
Plus, asking someone a favor makes her feel useful, which can be a generally pleasant sensation. So ask a new friend if she wouldn't mind bringing you a vodka soda from the open bar, and watch a sudden warmth bloom between you. (It's not just the vodka soda talking. It's SCIENCE.)