I always check out in person at the front desk and 90% of the time they ask if they want a receipt emailed to my email on file or printed out (I'll always ask for the email, sometimes for the print out too). The other 10% of the time I'll have to ask them for an email copy. Regardless I've never had a problem doing it this way.
That is my issue...I try to avoid having to physically check out whenever possible. I almost never have an issue with Westin, Sheraton or Marriott...it is all the sub-brands that seem to be problematic.
Thanks anyway.