Over many years I have noticed that Clark regards criticism of her or her Government as being disloyal to NZ, and she often gets hysterical when an Opposition Leader might dare say abroad that everything in NZ is not as rosy as one would like.
The excellent staff of the National Research Unit have found seveal speeches by Clark as Opposition Leader where she did exactly what she now arrogantly proclaims to be disloyal. Hypocrisy is one of the politer words for it.
Frankly the so called convention is something of a nonsense. With the Internet, overseas journalists, investors and governments can find out in detail exactly what is said by an MP about a country. To suggest that one should change your tune when actually overseas is silly.