Android automatically declines second call

[ryanmcclure4]

If a user is currently on a call on Android and they receive a secondary inbound call, the secondary call is automatically declined as per the following line:

void emmitCallReceived(PjSipAccount account, PjSipCall call) {
        // Automatically decline incoming call when user uses GSM
        if (!mGSMIdle) {
            try {
                call.hangup(new CallOpParam(true));
            } catch (Exception e) {
                Log.w(TAG, "Failed to decline incoming call when user uses GSM", e);
            }
            return;
        }
        ...
}

On the other hand, iOS is able to receive multiple calls just fine. Why is this code here for Android? Is the Android module incomplete and this catch was just placed here in the meantime?