Yes. This precise scenario happened to me at the Sheraton Needham MA in mid December of last year. No invoice under the door and on my way out, the front desk agent was polite, but absolutely refused to give me a printout of anything claiming it was a 3rd party booking.

(What it was was a prepaid spg rate booked through our corporate travel agency -- as required by my employer, as always. I think it's the spg PREPAID part that throws some of the front desk folks out there.)

Anyway, a manager was summoned who echoed that they would not print anything out for me. Very frustrated, I dropped my bags and pulled out my blackberry and pulled up the res along with the dollar amount, etc, etc. The front desk manager told me she'd make an exception "this one time" and only because I knew the precise dollar amount. I told her to look carefully and she'd see that this was a standard booking that involved a prepaid rate offered by the hotel's own website. I was met with only a blank stare.

I think all of this boils down to training on which prepaid rates can and cannot be viewed.