this logic can apply to almost everyone with a dangerous/dangerous jutsu.. eg
Who can beat itachi without knowledge? basically noone
Without knowledge you don't know to avoid eye contact
Without knowledge you will get 1 shot from tsukyomi
without knowledge you will get set on fire from amaterasu
etc
The thing is, Minato was very famous... eg, even though A and bee never saw him before, they knew of his ftg and the seals it uses...
So the only real people who would have no knowledge on minato are ninjas before his time. i.e tobirama, hashirama , madara...
Everyone else , even ofthe younger generations... definitely all the people of kakashi/gai's generation, should know of his capabilities, with seals etc and what he did on the battle field...
They may not know of ftg v2, or the fact that by touch he can mark you... but come on.. what non fodder would know not a thing? especially when ninjas seem to have knowledge of famous ninjas that existed all the way back to tobirama time....
If you're assuming the ninja has no knowledge of Minato, then Minato has no knowledge of the ninja he's fighting right? If that's the case then alot of ninja can rape him