All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
It is inappropriate for a Muslim who is allowed by virtue of a valid excuse to break his fast in Ramadan to eat or drink in public places during the day in Ramadan. This is because people who are not aware of the situation of such a person may misunderstand his actions and speak ill of him. Also, this action may encourage others who are not aware of that person's excuse to deliberately break their fast and openly commit such a sin.
A Muslim should call others to Allah through his words and actions. Consequently, it is not appropriate for a Muslim to be a cause, out of his ignorance, for the violating of one of the ordinances of Allah so as to incur the ensuing sin. It is incumbent upon whoever sees a Muslim eat or drink during the daytime of Ramadan to advise him in a kind manner and to gently explain the consequences of his doing to him.
Allaah Knows best.