I can see the logic behind unboxing it and testing to make sure it's not damaged, and working as it should etc to avoid disappointment, but it seems pretty unlikely these days that something like a tablet would be DOA (although I guess there's a higher risk if you get it from an independent seller in an auction site where there's a chance it might not actually be brand new or from some dodgy source of stock, say).
I never unbox or test things before giving them as gifts, if there's ever a problem I'd just take it back and return the item, but it's not happened to me yet!