Ha! Ford told me that, my fan would stay on after I turned my car off, I said it was the relay, the guy insisted its normal (even after I told him even after engine ran for like 10-15 minutes) I did what he said.... Then came to my car a few hours later and had a dead battery, I called ford and demanded them to jumpstart my contour because of their advice, gave me a bunch of BS and never did give me a jumpstart....
I think its just a liability sticker, You leave the battery in, fan shorts out and starts, you get injured, your fault...
They should put that on Laptops "Caution, Bottom of laptop may be hot!" No lawsuit there!