The only way around Belgium was through the Franco-German border, the route the Germans had taken in 1870, and now shielded by a formidable line of Fortresses.

The Germans expected to face little to no meaningful Belgian resistance, and largely discounted the British Army (moltke claimed he would send police officers to 'arrest' them). They didn't count on the heroic resistance of the defenders of Liege, nor did they count on the Belgians defending their country (though their claims of 'Francs-Tireurs' actions were HIGHLY exaggerated). They also didn't count on the BEF being able to put up the resistance that it did, at Mons and Le Cateau.

Hew Strachan, "The First World War, Volume One: To Arms!"; Peter Hart, "Great War: A Combat History of the First World War"; Christopher Duffy, "Through German Eyes: The British & The Somme"; Alan Kramer and John Horne, "German Atrocities 1914"; Max Hastings, "Catastrophe"

Loop around where exactly, what alternate route is there? Its either go straight to france or go through Belgium to get to france. This question needs clarification.