UBR is a no-go unless you pin it (which is a waste of a perfectly good $200+ stock).
Todd0000 is right on: just pin (and epoxy!) a collapsable stock in place. You want that epoxy on the receiver extension tube as well as in the hole and over the pin(s) you use. When done properly, someone would end up breaking your receiver extension and thus rendering the rifle inoperable if they tried to move that stock.
NY's AWB makes no sense at all, but goofing around with the provisions is just asking for trouble.

