I think the seller should have listed the machine as being sold "AS IS," if he didn't intend for a buyer to be able to kick the tires. Bidding would have been adjusted accordingly, of course.
But to advertise as "100% working" and not allow confirmation afterwards (which is in both parties' interests if they're both honest) is wrong.
Once again, if the seller felt that strongly about it, s/he should have advertised it as "100% working" but also "sold as is."