S!
Sure some amount of collisions did happen, but in CoD you only need to zoom through a formation and see them go crazy and get a few collision kills in the process. AI is too eager and starts to pull off these incredible ACM things in bombers
ANd of course regardless if they are in a formation or not. Seen them collide in a normal turn after bombing too.
I've read the US day raids had a fair share of midairs when they were attacked by Luftwaffe. Dodging falling planes etc. could mess up the formation and a B17 is not the most agile thing + about 800 planes around you = collisions inevitable.