Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: IB+ Gold, TK E+, Hyatt Globalist, Marriott LTP, IHG Diamond
Posts: 14,182
Not a problem, as long as you are aware that some hotels will automatically check you out if the room is obviously empty and unused.
As long as you make clear that your intention is to keep the room, you should be fine. Be aware that a Do Not Disturb sign is insufficent, as many hotels are obliged to check for deceased guests or arsenals of weaponry...