Personally I really don't advocate turning the bike upside down. Even nowadays when modern cable routing means the housings won't get bent or broken, it's still a lot of hassle, scuffage and extra dirt - and strength, too, if it's a heavier bike - for no real advantage.
+1
Computer, saddle, etc. all can get scuffed up this way.
Sarah
When it's easy, ride hard; when it's hard, ride easy.
2011 Volagi Liscio
2010 Pegoretti Love #3 "Manovelo"
2011 Mercian Vincitore Special
2003 Eddy Merckx Team SC - stolen
2001 Colnago Ovalmaster Stars and Stripes