>> If the RP detects that the account is possibly compromised, telling the
user to change their password is very likely the same thing as
informing the attacker that he's been detected. Since the attacker has
the password, he might as well change the password (and the account
recovery data) to lock out the original user.<br><br>In some cases it won't help, but in some cases it will (with the assumption that the website can tell that the password has been changed). For many websites that rely on basic methods of authentication there is no 100% guaranteed way of returning the account to the rightful owner. If a website has already learned through experience that this technique helps (and many have), then its a big barrier for them to become an RP if they know they are losing that technique.<br>
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