On Tradition: Even if the girl orders the wine, the waiter will bring it to the guy to taste.
In my experience, at "better restaurants" (and I know that phrase must set off snob alarms), the waiter will offer the taste to the person who chose the wine, even if a different person formally "placed the order." How does the waiter know who chose it? It is simple if the diners ask for more information on the wines they are considering, that way the waiter is involved in the selection process. But without that interaction, the waiter may have to guess based on who is holding the wine list. Without any information, the taste may indeed go to the guy.
Of course, if the waiter gives the taste to someone who did not choose the wine, that person should hand the glass to the person who did make the choice. The exception to this is that the chooser will sometimes offer the taste to someone else, for example to the guest of honor or to someone who has more knowledge of wine.