According to a number of previous articles she was giving a speech in Indiana that afternoon. Factcheck.org has now updated their page on this to say that she did come to New York that evening but had not arrived until after the time of the receipt and did not stay at the Waldorf.
Of course they do credit the Obama campaign with this information, but assuming Michelle Obama gave a speech at 1 PM in Fort Wayne, Indiana and concluded by 2 PM, I do not thing it is believable that she could travel 600 miles to New York, drive into downtown Manhattan, check into her hotel and sign the receipt for her room service all in the space of two hours.
As for the receipt, it is an obvious hoax. Besides the fact that the two signatures are identical, people on FR were changing the numbers on the receipt even after if was first posted.
ha! the time on the fake receipt! Now we’re using the fake evidence to disprove the hoax.
BTW, Factcheck is a project of the Annenberg Foundation, just as ACORN is.