Perhaps not but sellers do try their best to do the best by others and sometimes, that includes more than one potential buyer! You know, I would assume the person who bought the strings told you instantly they wanted them and would pay instantly? Its that simple for communication, yeah I want them, I'll pay you 'x' later today when home.
Just had a deal go through with, I'm gonna name him, Billy Apple, I told him I wanted the case but wouldn't be down his neck of the woods for a week however, through great comms, trust and instant replies, the deal went off without a hitch. Cheers Billy