Upside down by whose definition? Unless there is a specific requirement in the installation instructions that come with the receptacle or there is a local amendment to the NEC, there is no requirement that I'm aware of for any particular orientation.
This topic seems to come up a couple of times a year. If you do a search of this site, I'm sure you'll find a long thread about which way is up.
If you feel really strong about there being a right way & wrong way, submit a proposal to the NEC. But be quick, your time is running out. Look in the back of your 2008 code book for the form & the deadline.