Interesting. You could say that the way things turned out, they were partly right.
Although, on second thought, maybe the Germans would attack anyway, British or no British. If they didn't, Italy would face two total defeats, one in Albania by the Greeks, one in Lybia by the Commonwealth.
Those who have a much better grasp of logistics than I have shown Germany wasn't really ready to move until mid to late June anyway because of transport issues and the Rasputista. After that, Barbarossa was a six week gambit where Russia would surrender or the long siege would begin - and we know the outcome. But the miles on the engines, and the stress on the troops, was hardly worth the propaganda victory to Germany of taking Greece or parachuting down to take the island of Crete. Those troops certainly could have been used better elsewhere, and it just made the coastline Germany had to guard significantly longer with very little in return.