OK, I'll confess. It was me!
Actually, I don't know, but it happened to me. I had a habit of leaving the bay doors unlocked, in the back yard. Started missing gas. (My mileage went down, and eratic, until I got a locking gas cap. Now it's back up.) Next trip, after getting the locking gas cap, I went to put the sewer hose out, at a dump, and when I took the cap off to connect the hose, I got drenched. Both valves were open. I closed them, quickly, but not quickly enough. Changed clothes, took a shower, stored the clothes in a plastic bag in another bay. Hosed out the bay. Cleaned up the spill. (Didn't call the EPA.)
Now, I lock all bays unless I'm in one, at the time. When I go to the sewer bay, I check to make sure the valves are closed. Not doing that again! No, I don't think for a minute that I put the cap on and then opened the valves, myself. Some gas thieving jerk is probably still laughing. That's fine, I cut off his supply of gasoline!
We live and learn.
Ray D