I tend to hang it on the mirror...shiny side up! Most folks have a healthy fear of bikers. Short of carrying it with ya, it's fair game to anyone who really wants it.
From: Retired and living in the mountains of NE PA
I normally hang mine from the shifter peg.
Some of my helmets are small enough to fit in a saddlebag, so if I'm wearing one of them and am going to be away from the bike for a long time, I'll stow it in there.
pad lock to the quick release luggage rack. I figure, if they're going to steal it they will. But this way it keeps it on the bike, won't drop to the ground if it gets bumped. Nobody can grab it and run.
Do the helmet locks prevent someone from dropping a drink in your helmet or worse peeing in the helmet. Had a buddie with a wet helmet before. The helmet locks prevent theft but not wetness.>
Leave it on the mirror. I don't think anyone would steal it. Haven't so far anyway. Most people wont even touch the bike.
I do the same and have been lucky so far but some are not as lucky. Back about two months ago we were at the dealer when a guy rode in without a helment on. One of the guys standing outside with me yelled at him that we have a helment law in this state. He smiled and said he knew that and the police just got though reminding him also! He was at the Crackerbarrel eating and came out and his helment was GONE. He was just passing through and they told him where the nearest dealer was and while heading there to buy a helment he was stopped but the police did not ticket him.