The sick and travelers may be entitled to the legal dispensation not to fast during Ramadan. Because of that dispensation, their legal relationship to the day differs from that of a healthy resident required to fast.
The discussion therefore treats the effect of a sick person's or traveler's intention to perform another obligatory fast differently from the ordinary resident's intention.
This does not make all circumstances of illness or travel identical. The existence and conditions of dispensation and the juristic position being applied must be considered.
Legal principle: where the law has not eliminated competition between possible fasts, specification of intention retains significance.