You didn't specify which carrier you're on, but you can usually short check bags as you suggest. Just tell them when you check in, and make sure that you check the baggage tag before the bag goes shooting down the belt. When I do this (several times per year, and for the same reason as you), I never just leave it on the carousel. I always collect it and check it in a left luggage facility. (For me, this is almost always at LHR T3, and the left luggage place is very convenient.)

I wouldn't just leave the bag on the carousel for fear of what might happen to it. It might just be held as unclaimed for a few days, and eventually you would return and claim it. However, these days, it might be of interest to anti-terrorist authorities who might destroy it. Just not a chance I have a lot of interest in taking at all, regardless of how remote it may be.