In "Construction of Universal Bundles, II", Milnor has to replace the standard topology on the join with what he calls the "strong topology" which is the smallest topology such that certain maps are continuous. The purpose is to force the obvious local sections of his orbit map to be continuous, so that the orbit map will be a fiber bundle.
Essentially the same trick is used in later work of Hall on the generalized Whitney sum and in Str$\varnothing$m's "The Homotopy Category is a Homotopy Category."
My question: Is Milnor's paper the origin of this trick?