There was a scenario in which I and my co-worker were finding a piece of laminate, and then my co-worker said "it could be in the racks". Then I asked him can we say "it can be in the racks" and he said that both mean the same. I asked this to other co-workers (all of them are native Aussie and one is from England) and they said the same.
Even with different scenarios like someone called you and you couldn't recognise him then you can say "it can be John" or "it could be John". I asked three or four of my co-workers and they said in all scenarios where possibility is involved "can" and "could" are synonyms.
I always thought that "could" signify a greater uncertainty than "can". Also, this post completely rejects the usage of "can" in specific situations which is even more strange.