you are mixing two situations.
If you decide you don't want a receiver any longer on your account, and it is "leased", DirecTV in principle wants it to be returned for reuse. If it's an older model, instead of returning it, they might ask you to return just the access card, or maybe nothing at all. If you keep the receiver, you MIGHT be able to reactivate it in the future but only on your account - you can do this right now but we don't know if this will continue.
If you want to deactivate a leased receiver on a temporary basis, you can't. If you deactivate it as I described above, you can't guarantee what DirecTv will do. They might ask for it back, or the access card. So you might lose the equipment forever. Yes, it's a loophole that might work for you. But also you might be out an expensive DVR. If you want to take the risk, I guess that's up to you.