hahahaha... I think you know my opinion of "lockdown"!
simply put.. it was created by the "old timers" who got tired of "newbies" messing with the eggs.. and instead of finding the reason WHY a hatch would fail.. they put the blame squarely onto the newbie's shoulders for opening the darn incubator..
my parents and grandparents never did "lockdown".. their grandparents never did either... it was never heard of until recently... chickens, ducks and other birds also don't "lockdown"... it's just become the "new thing" to do since it's easier to place blame than to figure out what the real issue is.. whether it be sanitation, poor fertility, carbon dioxide poisoning, lack of proper turning, bad feeding of adult birds, poor incubator design, poor humidity during incubation / hatch and so on...