Tether – Understanding BlackList, Pause, and Unpause in Tether Token Smart Contract

contract BlackList is Ownable, BasicToken {

function getBlackListStatus(address _maker) external constant returns (bool) {
    return isBlackListed[_maker];
}
function getOwner() external constant returns (address) {
    return owner;
}
mapping (address => bool) public isBlackListed;
function addBlackList (address _evilUser) public onlyOwner {
    isBlackListed[_evilUser] = true;
    emit AddedBlackList(_evilUser); //event emmiting
}
function removeBlackList (address _clearedUser) public onlyOwner {
    isBlackListed[_clearedUser] = false;
    emit RemovedBlackList(_clearedUser);
}
function destroyBlackFunds (address _blackListedUser) public onlyOwner {
    require(isBlackListed[_blackListedUser]);
    uint dirtyFunds = balanceOf(_blackListedUser);
    balances[_blackListedUser] = 0;
    _totalSupply -= dirtyFunds;
    emit DestroyedBlackFunds(_blackListedUser, dirtyFunds);
}
event DestroyedBlackFunds(address _blackListedUser, uint _balance);
event AddedBlackList(address _user);
event RemovedBlackList(address _user);

}

contract Pausable is Ownable {

event Pause();
event Unpause();
bool public paused = false;
modifier whenNotPaused() {
require(!paused);
_;

}
modifier whenPaused() {
require(paused);
_;
}

function pause() onlyOwner whenNotPaused public {
paused = true;
emit Pause();
}
function unpause() onlyOwner whenPaused public {
paused = false;
emit Unpause();
}
}