It is sending clear messages.
Second, we have to look at the consequences of not complying with a rule like that. In Quebec, the only consequence is moral authority based on what editorialists say and so on, but the minister will not go to jail. In some other provinces, however, when a deficit is looming, the ministers see their wages cut. The consequence is not the same, and I am not sure whether the impact is stronger, but you see how you can play with either the ministers' wallets or the media reaction to the news.