Answer:
It depends entirely on the other person, and a bit on how you deal with them.
If you left them with no answer, it depends on how they react to the situation. This involves your relationship with them, as you know best how the other person would feel if you ghosted them.
With that in mind, if you had to tell them no, how you told them counts. Say you told the other person politely that you couldn't do as asked. It is possible that they won't feel as bad as being ghosted, but again you know best of this persons personality and how they will react to the given situation.