If its cheap, or I plan to modify the hardware/ product myself then I will.
I will never buy an open box gift, or high priced item. It has to be new.
But like Dauntae says, It cant be sold as new if its been used / or was a display.
If your unsure, or change your mind, return it. If you think they'll get difficult, find an issue with it, or say the battery doesn't last as long as specified (thats my excuse) as no device lasts the time it says on the spec sheet lool.
I say - Ive charged it, not even used it long and disabled everything on it, dimmed brightness etc and batteries gone in X amount of time so it doesnt last Y as stated.... I want a refund.