I recently downloaded Camille Saint-Saëns' lovely Valse nonchalante—the Durand First Edition (1898)—from IMSLP. All the upper-staff reminder accidentals are placed above the staff. I don't remember seeing this style before.
I don't have that many Durand scores, so I don't know whether they've maintained this policy. On the one hand, I like it because it distinguishes reminders from true accidentals without the clutter of parentheses. On the other, placing them above perhaps makes them a bit too prominent. (I assume reminders in the lower staff would be placed below.)
I'm curious whether any other publishers adopt this style and what others think about it.
Note that this placement is, of course, practical only when there is a single note. In his Valse canariote (also Durand) we have the usual parentheses (and smaller type) in m. 3 here:
It may be for this reason that we rarely encounter this placement in modern music.