The only time I've gotten a time capsule request in the 4 years I've had New Leaf I accidentally opened it without thinking and the villager who gave it to me was really annoyed!!!
I usually bury them when I get this request. I just bury them in my beach area. It a pretty easy request for me to do, so I don't mind doing it for them. It is a lot better getting the bugs or fishes for them in my opinion. Because they might put those in their homes. :/How many of you actually bury them? Sometimes I do, sometimes I just leave them in my letter area. Then I completely forget about it and the villager will move out or just never ask for it. lol
I love opening presents because I usually forget to deliver those anyways(plus I hate it when they change into a terrible gifted shirt) Btw maybe you never got a time capsule request because your letter pockets were full :'D I've gotten quite a few over the years.
I bury them right after the conversation ends and I bury it beside their house so I don't forget where I put it or dig it up accidentally thinking it's a fossil/gyroid.