We still split ops. There are greater concerns than deniability, they were not so ignorant back then that they thought a guy bailing out of an SR-71 could pass himself off as a lost businessman - the concern was actually cold war vs hot war. Having CIA officers conduct ops was expected in the surveillance/counter-surveillance game, the only repercussions for those ops being exposed were nasty letters and embassy staffers being expelled. Conducting military ops over a sovereign nation could be considered an act of war.