My friend told me that there is some risky if i using the pokemon that i catch before the releasing day, cuz nintendo might find out these pokemon. He not sure with that but i got some nervous(.
The other reason i want to used the old save file because i got a shiny Decidueye for the first time, so I don't want to leave him
I've not heard of anyone being banned due to their save file start dates or caught dates on Pokemon. For all Nintendo knows, the time/date could have just been set incorrectly on your 3DS. Shouldn't be a bannable offense at all.
