I found a way to choose any calling card even the ones that are locked (master or supply drop), but there is a problem:
- the game won't save the calling card while restarting
- the calling card is displayed inside the matchmaking lobby but sometimes not visible ingame (ex. calling a uav or other killstreak)
Changing/adding thing you shouldnt have like killstreak, camo,attachments calling card will get you vac ban xD.
Good amount of people that change thing like killstreak and camo or edit memory with cheat engine got vac later.