Sometimes Nancy had to snoop incognito and used an alias which she paired with a disguise every once in a while. When the aliases were transparent like "Nan Drewry," she often was found out but her disguises often helped when paired with an alias.
Some of Nancy's aliases:
Nancy managed to outwit the villain in The Whispering Statue (revision) when she sleuthed under the alias Debbie Lynbrook and wore a disguise--self-tanning lotion and a dark wig and glasses. The villain in the end screamed, “Your hair! You were wearing a wig that half-covered your face! You’re Nancy Drew, not Debbie Lynbrook!”
Best way to avoid being detected with a good or bad alias: a dumb criminal!
Here's an article I wrote back in 2005 on Nancy's aliases if anyone's interested. If you want to disguise yourself as Nancy Drew there's always the Nancy Drew costume shown in a recent Blog entry here--you might see one at eBay someday!