What's wrong with promising to send banners but not sending them?

If you promise to send someone a banner, what's wrong with not sending it? First of all, people will think that your integrity is not good. After all, people will think that you are a man of bad faith. Sending banners by yourself is usually to thank others for their help or to say something else. Naturally, if you promise to send someone a banner, you must give it to them. If you break your promise to others, it will be bad for yourself and others, unless you have any special reasons.