When someone speaks of cards that can be done with a "borrowed" deck of cards, that usually means that someone hands you their deck of cards, and you start performing. It does NOT mean that someone hands you their deck of cards, and you excuse yourself while you retreat to a private area to set up your stack.

Yes, the Lolita System is a stack. It's not a stack that will stand up to scrutiny, because there's too much of a pattern to it, and it's missing cards that people tend to notice. The main purpose behind this stack is that you are able to know things about adjacent pairs of cards. This is actually a very interesting property, but it means that in every effect, when you ask a spectator to "choose two cards", they have to be two cards that are next to each other in the deck. Frankly, this is an odd restriction, and many spectators will automatically assume that this is part of the explanation as to how the effect was accomplished.

I love stacked deck and memorized deck work, but this is not a stack I'd ever use, for the reasons given above. Nor would I refer to my stacked/memorized deck work as effects performed with a "borrowed" deck of cards.