I usually forget to use the hanger. Some of my CV's have them and some don't. Something I do if loading the bike in the car without the rear wheel is to put a dowel or old spoke through or behind the dropouts to hold some tension on the chain. Kinda hard to forget to remove the dowel or spoke when reinstalling the wheel. I also have this yellow plastic thing that Nashbar used to sell that you use to hold the chain around the end of the dropout. Kinda nifty, but it gets all greasy and a PIA to store.