Does anyone really need to know in the first place? If it comes up I wouldn't say anything simply because it's none of their business - just as the way their child sleeps isn't really any of your business either kwim? It's not something you should 'hide' by not saying anything, but I would just shrug it off - you have to do whatever it is that gives both of you the max amount of sleep you can get - for some that will be co-sleeping and for others it will be cot sleeping because not all babies will do what you want them to do because they don't read parenting books

We actually have our youngest back in our room in his cot because he sleeps better in our room than he did in with his brother and I don't know when we will move him back. He wont have a bar of cosleeping anymore so I don't push the issue because there is no point.