"... people pay attention and do the smarter thing..."

Some do, some don't. As you enter the Kern River Canyon, near Bakersfield, CA, there is a sigh saying how many people have drowned in that river (Meryl Haggard even made a song), yet every year more people go in and don't come out. But, since that place is a posted hazzard, survivers (there are a few, from time to time) should be charged for the cost of the rescue.

Signs are often ignored, but their presence can shift liability...