DH and I always seem to know what we're getting at this point, so it really doesn't matter anymore.
When my sister and I were little, we'd tear the house apart looking for Christmas presents. Under the bed? Nope! In the basement? Nope! Ahhhh, the cubby hole in the attic? Yep! Which meant that we had to get into my parents closet, open the door in the ceiling, bring the steps down, climb up, and snoop. Try doing that without getting caught.

We also used to go out to the camper to snoop until our parents finally caught on and starting taking the camper key with them to work. Darn it.
I always seemed to know what was going on. One afternoon, I stopped at my parents for coffee.....only to find my mom and my aunt wrapping one of my presents: a lovely ceramic apple pie pan with an apple lid. Mom got so disgusted with me that she and my aunt would start wrapping my presents at the last minute because my aunt had all my stuff in her apartment. It was the only safe place.
Several years ago, when we started buying gifts online, I was checking my home email at work....and found shipping confirmations for several cooking items that DH had ordered for me for Christmas. (No, I don't consider cooking items as bad gifts; I do, however, hate receiving any cleaning item as a Christmas gift.) I never told DH that I "peeked" in the emails.
I'm kind of hopeless when it comes to presents.