My question is how the stake.com team knows that the account has been bought / sold ? is it only based on other users' reports?
It's nothing new I've seen this since last year someone gets an email from stake.com offering a deposit bonus then the offer is sold to another user, I'm sure he has more than one account.
One a few reasons they can ask you for security reason
- The email change
- Password change
- Login with different IP Country, Let's say the original owner form Asia and suddenly there has some change login and playing with Europe IP.
IMO its up to everyone sell or buy some account, but when this situation comes up just don't begging, cried and other thing. If you buy or sell the account to other people, you must know the responsibility.