Not really. We'd rather consider it the prospect of sheer stupidity on the part of the Allies, a stupidity that would actually be rather feasible. Sickle-Slice IOTL worked by a very, very narrow margin, narrower than most OTL histories acknowledge. It is literally possible for France to reinforce that area by artillery alone and stop the German offensive without sending a single rifleman more.
IOTL 1940 was preceded by several factors:
1) The Allies wanted to prepare for a long war, not a short one. They were planning for an offensive in 1941. They quite rightly suspected the Germans were weaker, and the German *generals* weren't wanting to initiate anything before 1941 themselves. Thus the Allies were developing a plan offensively to counter the initial German plan of OTL.
2) That plan was precisely what the Allied 1940 action was designed to counter. It really would have done that had it not been for the TL-191 type incident where the plane fell with the actual German plan and the Germans, instead of adhering to the plan, decided to change it. Sickle-Slice unfolding as it did was not ASB, the incident of the plane in Belgium is the one thing about it all that would qualify for an ASB incident in some TLs. What *that* was was mere human error.
3) The German triumph of OTL again was an extremely narrow margin of success. The French had their least-prepared troops, a lower amount of artillery, and poor air support, and the Germans made it by a margin that suits perfectly for a tactical AH POD, as not at all battles do.
4) The ultimate decisive factor was the poor allocation of reserves by the Allies, and this is not ASB at all, it's just stupidity.
