There are any number of books about the start of WWI. Read Europe's Last Summer by David Fromkin. I read another one about the same time, I can't find the title right now. They all make the same points: 1) the common narrative about WWI is that nobody had any idea a war might start until the assassination of the archduke lit the fuze and the world blew up and 2) no serious historian believes that narrative.
The British and Germans were locked in a naval arms race that consumed large chunks of their national economies. The Germans had been working on war plans for decades, and acting on those plans. They built huge railroad platforms in every city so they would be able to load troops on trains quickly when the war started. The put together elaborate timetables of which units would go where and when. The built the largest siege guns in the world with the specific intention of using them to pulverize Belgian forts when they violated that country's neutrality.
Meanwhile, the French and Russians were drawing up coordinated plans to invade Germany from two directions.
This is not a picture of world that has no idea there's going to be a war.
Top all that off with the fact that what happened is nothing like what the WTBS said was going to happen.