[joemi]

I would assume it's more due to them not realizing that this isn't just something that periodically happens at the park (like Old Faithful). It might seem unusual, but they don't know how unusual or dangerous it is. It might just be no more unusual than a low road near a body of water that gets a tiny bit flooded in one spot after a heavy rain -- the kind where locals who know about it just drive through because it's only an inch or two deep but visitors might be more hesitant about. In the case of this explosion, the aftermath video shows that it was indeed very unusual and dangerous.