DEAR MISS MANNERS: If I receive stationery as a gift, is it best to write the thank-you note on that stationery?
GENTLE READER: Etiquette may not, strictly, require it, but it is certainly best, as it avoids any implied criticism that you would have preferred something different.
Miss Manners realizes that not all gifts are given by someone in a charitable frame of mind: Gentle Readers have informed her of stationery being given as a way to signal a dissatisfaction with prior thank-you notes (or the lack thereof). But she also chooses not to look for trouble.