I would never say there is such thing as a lock however there are instances when teams go to a 70% or even more of lock situation.
for instance
never has a superbowl ever went into overtime
the chicago cubs have not won a world series in over 1oo years
seattle has never won a world series
cleveland has never been to or won a superbowl
detriot lions have never been to a superbowl
detroit lions have never beaten the washinton redskins in washington
in march madness a 16 seed has never beaten a # 1 seed