Last year I managed to get all my cc's blocked (long story). I had booked a room with an IHG property in the US, secured with the (now blocked) card. So at checking they didn't give me the room. I was allowed to check in by giving $300 (or $200?) in cash + prepay the room (also cash). Was a hassle to get the money back in the morning, but it worked out. I also paid a room at another US hotel all cash + security deposit without reservation. I called ahead to make sure they would accept it. No problem, but you do get some funny looks from other guests when checking in/out.