In this case it is most probably high competence. Coming out of WW2 it wasn't difficult to take national security extremely serious. I thought that there wasn't much to the crash(es) near Corona in 1947 but the witness testimonies are just very very convincing, I actually changed my mind after reading up on the subject recently (before I would have said I don't know anything about it but I'd be amazed if it was true).
A lot of observations had been made the weeks previous to the crash and gathered a lot of headlines, including the one in Portland that coined the expression "flying saucer". The person in the photo with the weather balloon is on record saying that it was not a weather balloon, that was a cover story, as are a lot of other people involved in the handling of wreckage and bodies in the days after. These are people that didn't come forward but had to be found after several decades.
And this was the press release by the military before it was withdrawn and replaced with the balloon story:
"The many rumors regarding the flying disc became a reality yesterday when the intelligence office of the 509th Bomb Group of the Eighth Air Force, Roswell Army Air Field, was fortunate enough to gain possession of a disc through the cooperation of one of the local ranchers and the sheriff's office of Chaves County"
I encourage anyone who is interested to look at Stanton Friedman's interviews with witnesses, they are on youtube.