A You're right - there are lots of theories doing the rounds about how to wash "stemware". Some people believe that glasses should be rinsed thoroughly in piping hot water, which may or may not be sufficient to kill whatever oral bacteria linger on the rim. After that, the purists argue, glasses should be left to stand so the moisture can evaporate naturally.
Others argue that a mild detergent is fine, especially if the glass is rinsed after the wash.
Some people seem to be more sensitive to washing -up liquid residue
than others - you're best avoiding the more extreme "pineapple and pomegranate" type varieties. Champagne experts also argue that small traces of detergents prevent bubbles from forming so readily in flutes.
Repeatedly washing glasses in a dishwasher can potentially dull the surface with tiny scratches, so whether or not you use soap, the experts seem to agree that this is a task best done by hand.