I really wonder why the Devs never be more strict to the owner of every Dota 2 account where everyone must pay a high amount of cash to the Devs or at least (compulsory) purchase any hero arcana if a player want to change or modify the "associated mobile number." ~ The purchased arcana will be non-tradable and cannot be "gift wrap".

In addition, if the associated number of the account is changed or modified, then the account will be restricted to join "Ranked Matchmaking" for 10 years because I think the "Steam Guard Mobile Authenticator" is a very good enough application to prevent any player from losing his account.

Why do the Devs allowed a new number to associate to the account? Allowing a new number means you are allowing public to change ownership in other ways. Totally a stupid Devs system I ever seen where game like Dota 2 will allow new number to be used when the current associated number (Dota 2 Phone) is removed.

Why the penalty is given to the old number?
Why the penalty isn't given to the account or the user who owns the account?