Down in SoCal they'e starting to enforce the "Carbon Monoxide Warning Sticker Law" that went into effect in 2005. Applies to all boats whether new or used sold in California after 2005 to display one on the transom and one on the dash area visible to the driver. Here is a link to the assembly bill:
The stickers are free and can be obtained at the DMV.
It's only a matter of time before they start using that as a reason to make contact out on the delta so I just thought I'd throw it out there.