Ummm... it really doesn't sit right with me either. The first thing I thought of was fire safety. Then I wondered how she felt about being locked in her room? I know at that age (at any age really) my kids would be distressed by being locked in. Is there any other way? A lock on the bathroom door, as a PP suggested? And a baby gate at the top of the stairs? Would she climb over it if it was at the top of the stairs? It's a tough one, but I really don't think I could lock my kids in.