I grew up with seeing that sign on the Hope-Princeton and always thought it really got the message across.  It is my understanding that some small group eventually complained about its “appropriateness” and “not politically correct” and that is why we no longer see it.

You might be interested in these tidbits from the internet regarding the sign:

Apparently, the “Big Burn” of August 8 to 31, 1945 was caused by a motorcycle tourist’s or surveyor’s cigarette or campfire which destroyed 5,920 acres (2,396 hectares) of forest. This would have been before the paved highway was completed in 1949.  Parks Branch records show that it was actually a prospectors campfire that started the conflagration… but no reason to let that get in the way of getting a fire protection message across.
The original sign didnt have the cigarette, and read “One camper made this 5000 acres look like Hell! Dont you be careless!” They had to replace it, as “Hell” was pretty tough language in the early 1950s.

From the Ministry of Forests: The highway follows along the Skagit River through an area that is known as “the burn”. “The burn” was caused by a tourist throwing a lit cigarette into the forest in 1945. The fire destroyed over 2,000 hectares of forest and was subsequently replanted

And here’s a picture of the original sign:

Thought you might find this interesting.

Irvin Redekopp